Answer in brief
Design the front panel around four things a shopper must recognise at once: who the brand is, what the product is, which variety it is and how much is in the pack. Check that they survive at thumbnail size, keep the online image recognisably the same pack, place the barcode on the back away from seams and edges, and test both the printed mock-up on a shelf and the image on a real phone before approving print.
The same pack is now judged at two sizes
For most of its history a pack had one moment to win: on a shelf, at arm’s length, among its competitors. That moment still exists. But the same design is now also shown as a small square in a scrolling list on a phone, next to a price and a button, often to someone doing something else at the same time. Both viewings ask for recognition, under very different conditions.
GS1, the standards body best known for barcodes, wrote a guideline about exactly this shift. Its Mobile Ready Hero Images Guideline says the move of online retail from desktop to mobile creates three problems: the physical size of the screen, fast momentum scrolling, and shoppers who, for everyday items, decide more or less instantly. It adds a detail packaging designers rarely consider: on a digital shelf, all products appear to be a similar size.
The usual workflow, designing for the shelf and then photographing the result for the web, treats the phone as an afterthought. A better order is to decide the hierarchy once and prove it in both places before anything is printed. The sections below follow that order: what the front must say, how it survives shrinking, what the online image may change, where the barcode goes and how to test.
Four answers the front of the pack owes a shopper
The GS1 guideline condenses its research into four questions, which it calls the 4Ws: who is the brand, what is it, which variety is it, and how much of it is there. The document says the list rests on qualitative and quantitative studies, including shopper journeys, eye-tracking and A/B split tests. Its aim is that someone who has bought the product before can recognise it without reading the title or even noticing the price.
Treat the four as the brief for the front panel. Not every answer needs words. GS1 points out that a bottle of water does not need the word “water”, and that a variant strongly associated with a colour is identified by that colour. What matters is that each answer can be found in a glance, by shape, colour or a few large words.
Everything else on the front competes with those four. Claims, award badges and secondary copy all take space from them. The guideline allows one addition where a category needs it, such as an age range on pet food or a size on nappies, and calls it the “plus one”. It is explicit that this is not a marketing message. A physical pack has more room than a thumbnail, but the discipline is the same: decide what the front must say and move the rest to the sides and back.
A hierarchy that survives being shrunk
The quickest way to see a pack’s real hierarchy is to reduce the front panel to the size it will have in a product listing. GS1 describes what usually happens. Shape and colour are likely to be preserved, and logos may stay recognisable even when their detail is lost. Text set in the brand’s style is where one or more of the four answers stops being clear.
So put recognition into the things that survive. A distinctive block of colour, a silhouette, a variant name set large and plainly, and strong contrast between type and background all carry further than fine detail. When the guideline discusses clarity tests it points to the 4.5:1 minimum contrast from the W3C’s accessibility guidelines as an international definition. That is a sensible floor for the variant name and the quantity on the pack as well as on a screen.
Format matters too. According to GS1, tall and thin or short and flat products fill only a small part of a square image, which makes them the hardest to present clearly. A bottle or a tube therefore needs larger type and fewer elements on its label than a carton with a broad face. The guideline also warns that the problem is sharpest when one product comes in several sizes of identically shaped packaging, so give each size an unmistakable marker.
The hero image is the pack, tidied, and nothing more
GS1 defines a mobile ready hero image as a representation of a real product that may differ from a standard pack shot but keeps most of the physical pack’s key elements of design, shape and colour, so that it is recognisable on a digital shelf. Within that definition the brand owner has real freedom. Text that is illegible at small size can be removed, the four answers can be enlarged, and the guideline accepts a medium zoom of up to 150% where the full product does not need to be shown.
The limits are just as clear. New design elements that are not on the physical pack should not be introduced. Anything moved to the front must exist elsewhere on the pack and must convey one of the four answers. Enlarging text until it breaks out of the pack outline, or adding badges around the pack, is described as non-conformant. The guideline’s own summary is the best one: think of it as a simplified pack design, not an advertising banner.
This is the strongest argument for designing pack and image together. If the simplified version is planned with the artwork, the brand decides what may be dropped and what may grow. If it is not, each retailer or agency will improvise its own. Two cases need planning early: for packs printed in several languages GS1 recommends one hero image per language group, and for multipacks it asks that a single unit be shown outside the pack.
Channel rules push the message back onto the pack
Sales channels publish their own requirements for the main image. Google’s Merchant Center help is a good example, and it points in the same direction: it asks for an image that shows the entire product with minimal or no staging. It does not accept promotional elements: calls to action, promotional adjectives, watermarks and other overlays, or borders. Brand names and logos are allowed only when they are an inherent part of the product itself.
Google’s page also gives framing advice. It recommends a solid white or transparent background and a product that takes up no less than 75% and no more than 90% of the image. For a product shown in its packaging, the image should display the pack in more than one dimension and not just its front. Channels can also part ways with the GS1 guideline: where GS1 wants a multipack shown with one unit beside it, Google says the main image of a multipack should show a single unit.
Two conclusions follow for packaging. First, whatever a shopper needs to know at thumbnail size has to be printed on the pack, because on these channels it cannot be added as a caption over the picture. GS1 gives further reasons to avoid text added to the image: it is invisible to screen readers and, the guideline notes, is not accepted by everyone, including at least one major search engine. Second, the rules move. Google’s page currently announces a higher minimum image size from 31 January 2027, a reminder to check each channel’s page instead of an old brief.
Where the barcode goes, and where it must not
The back of the pack carries one element with hard requirements. GS1 Sweden’s placement guide says to put the barcode low on the back of the package, preferably to the right, and, where possible, at least 8 mm and not more than 100 mm from the edge. It should sit on a smooth surface, never around a corner or over a joint, perforation or seam, and not on the bottom of the package. Each package carries only one barcode.
Shapes have their own rules in the same guide. On cans and other cylinders less than 12 cm in diameter the barcode is recommended to run like a ladder, with the bars stacked as rungs, not like a fence. On bags and soft packaging it goes at the centre, where the risk of wrinkles is lowest. On bottles it belongs on the main label or a separate label on the back, never on a band around the neck. Where a pack is wrapped in film, the joint of the film must not cross the code.
For the designer this means reserving the barcode zone on the dieline at the start, not squeezing it in at the end. Mark the seams, folds and glue flaps first, then place the code where none of them reach. To make sure a code can be read, the GS1 Sweden guide recommends having it verified, and a printed proof is the moment to do it. A code that fails at the till is a packaging defect, however good the front looks.
Two proofs before print: the aisle and the phone
The shelf proof is physical. Print the artwork at actual size, fold it into a real pack and stand it among the competing products it will actually sit beside, at the height it is likely to be stocked. Step back to arm’s length, then further. Ask someone who has not seen the design to find a named variety, and watch where they hesitate.
The phone proof needs the same honesty. GS1 warns that it is all too easy to judge a design on a large desktop screen and then shrink it, which is not the same as viewing it on a handheld device, perhaps in poor light. It also asks that images be judged in the context of a digital shelf, with other products around them, and not in isolation. So paste the image into a screenshot of a real category page and look at it on a phone.
For a repeatable check, the guideline recommends the See-It test from the University of Cambridge Engineering Design Centre, while noting that when it was written there was no single internationally recognised standard for visual clarity. It also describes a quick simulation: a Gaussian blur with a radius of 34 pixels on a 3000 by 3000 pixel image approximates an image shown at 16 by 16 mm on a phone held 40 cm away. If the four answers survive the blur, they will survive the listing.
One approval sheet for both shelves
Collect the results on a single page that is signed before print. It lists the four answers and where each sits on the front panel, then the result of the shrink test and the contrast check. It shows the approved hero image with the changes it makes to the pack, and the barcode zone with its verification result. The last line is the date on which each sales channel’s image rules were read.
The page needs four signatures, not one: the brand owner, the designer, the printer or prepress house for the dieline and the code, and whoever manages the online listings. The order of work matters as much. Front-panel hierarchy first, then the dieline with the barcode zone, then the hero image derived from the approved artwork, then both proofs. Reversing it means discovering on a phone what could have been fixed on paper.
Keep the limits of the evidence in view. GS1 states that its guideline is aimed at replenishment items, familiar products bought again and again, on handheld screens, and that it does not cover high-value or infrequently bought goods, where shoppers take more time. It also reminds readers that adopting a GS1 guideline is voluntary, so ask each retailer which image conventions it accepts. The principle holds either way: one hierarchy, proved twice.
Practical checklist
- Write down who, what, which variety and how much for every product, and mark where each answer appears on the front panel.
- Shrink the front panel to listing size on a real phone and remove or enlarge whatever cannot be read.
- Plan the simplified hero image together with the pack artwork, using only elements that exist on the physical pack.
- Reserve the barcode zone on the dieline: low on the back, clear of seams, folds and edges, and have the printed code verified.
- Read each sales channel’s current main-image rules before the shoot and note the date on which you checked them.
Questions and answers
What is a mobile ready hero image?
It is the main product image prepared for small screens. GS1 defines it as a representation of a real product that may differ from a standard pack shot but keeps most of the pack’s key elements of design, shape and colour, so that shoppers recognise it. In practice it is a tidied version of the pack front in which the brand, product type, variety and amount are easy to read at thumbnail size.
What information belongs on the front of a product pack?
The four things a shopper uses to pick the right item: who makes it, what it is, which variety it is and how much is inside. Some of these can be carried by shape or colour instead of words. Detailed claims, instructions and the barcode belong on the back and sides, where they do not compete with recognition. Mandatory labelling is a separate question: check the rules for your category and market, because some of them prescribe what must appear on the front.
Where should the barcode be placed on retail packaging?
GS1 Sweden’s guidance is to place it low on the back of the pack, preferably to the right, on a smooth surface and, if possible, between 8 mm and 100 mm from the edge. Keep it away from corners, joints, perforations and seams, and avoid the bottom of the pack. Cylinders, bags and bottles have their own recommendations, so check the guidance for your pack shape and have the printed code verified.
Can text or badges be added to the main product image online?
It is safer to assume not. GS1 treats text added to the image, outside the pack itself, as non-conformant with its hero image guideline, and Google’s Merchant Center rules reject main images with promotional overlays, watermarks or borders. Put essential information on the pack so that it is part of the product, and use additional images and the product page for everything else.
How do you test packaging for thumbnail legibility?
Look at the image on a real phone, at listing size, among competing products, and ask whether brand, product type, variety and amount can be read at a glance. GS1 recommends the University of Cambridge’s See-It test for a repeatable result. As a quick studio check it describes blurring a 3000 pixel square image with a 34 pixel Gaussian blur, which simulates a small image held at arm’s length.