What resolution does a billboard need, and can AI images work?
About 12.5 to 25 pixels per inch at full size. Lamar prints bulletins at about 12.5 ppi, so a 14 x 48 foot board needs a 7200 x 2100 pixel file. OUTFRONT’s Los Angeles spec asks for 25 ppi, or 14,400 x 4200. Digital billboards take a 1400 x 400 file. A 4K AI render comes close to the print sizes and any 1K render covers digital. Set the words and logo as vector type, and check the product at full size.
Resolution by format, from the media owners’ specs
| Format | Size | What the spec asks for | File in pixels |
|---|---|---|---|
| Printed bulletin, Lamar | 14 x 48 ft | 1/2 in = 1 ft at 300 ppi, about 12.5 ppi at full size | 7200 x 2100 (7350 x 2250 with the 6 in bleed) |
| Printed bulletin, OUTFRONT Los Angeles | 14 x 48 ft | 1 in = 1 ft at 300 ppi, 25 ppi at full size | 14,400 x 4200 (about 14,800 x 4600 with bleed) |
| Printed poster, Lamar | 10 ft 5 in x 22 ft 8 in | 1 in = 1 ft at 216 ppi, 18 ppi at full size | 4896 x 2250 |
| Digital bulletin (Lamar template, OAAA standard) | 14 x 48 ft and similar | RGB file, 7:2 | 1400 x 400 |
| Digital large bulletin (OAAA) | Large bulletin class | 3:1 | 1800 x 600 |
| Digital poster (Lamar template, OAAA) | Poster class | 21:10 | 840 x 400 |
| Digital transit screen, OUTFRONT New York | Vertical screen | 9:16, 15-second spots | 1080 x 1920 |
| OUTFRONT Livescape, New York subway | 11 screens in a row | One file across all 11, with 221 px gaps between screens | 14,090 x 1920 |
The same 14 x 48 foot board gets a 7200-pixel-wide file from Lamar and a 14,400-pixel-wide file from OUTFRONT in Los Angeles. Ask the media owner for the spec sheet for your exact unit before you render anything.
Why so few pixels are enough
Billboards are seen from far away. Eye charts are built on the fact that a person with 20/20 vision can make out detail about 1 minute of arc wide, which is 1/60 of a degree. From that you can work out how close someone has to be before a single pixel shows:
| File | One pixel on the board | A 20/20 eye sees single pixels from closer than |
|---|---|---|
| Lamar print, 12.5 ppi | 0.08 in | About 23 ft |
| Lamar poster, 18 ppi | 0.06 in | About 16 ft |
| OUTFRONT print, 25 ppi | 0.04 in | About 11 ft |
| 1400 x 400 digital file on a 48 ft board | 0.41 in | About 118 ft |
| 720-pixel-wide LED face on a 48 ft board | 0.8 in | About 229 ft |
Lamar’s templates list 14 x 48 foot digital faces that are only 624 to 936 pixels wide. Your 1400 x 400 file is scaled down to fit the board, so fine texture in the file does not show on the road.
Can an AI render reach billboard size?
| Model and setting | Largest output | Against Lamar’s 7200 x 2100 bulletin |
|---|---|---|
| Nano Banana 2, 4K, 4:1 | 8192 x 2048 | Crop to 7022 x 2048, then enlarge 2.5% |
| Nano Banana Pro, 4K, 21:9 | 6336 x 2688 | Crop to 6336 x 1848, then enlarge 14% |
| GPT Image 2.5, widest allowed (3:1), a size OpenAI calls experimental | 3840 x 1280 | Crop to 3840 x 1120, then enlarge 1.9 times |
| Nano Banana 2, 1K, 4:1 | 2048 x 512 | Already larger than a 1400 x 400 digital file |
For print, render the approved shot again at the largest size and widest shape the model offers, then enlarge the rest of the way. OUTFRONT’s 25 ppi spec needs about twice the enlargement: roughly 2x even from Nano Banana 2’s 4K output. For digital boards, resolution is not the problem at all.
Upscaling: what it fixes and what it makes up
An upscaler enlarges an image and fills in detail. Photoshop’s Generative Upscale, for example, offers 2x or 4x with three models: Firefly Upscaler, for files up to 6144 x 6144 pixels; Topaz Gigapixel, which Adobe says preserves existing detail, up to 56 megapixels; and Topaz Bloom, which Adobe says adds new, creative detail, up to 9 megapixels. For a product, pick a model that preserves detail. One that adds creative detail can change a label, a logo or a stitch pattern.
- Enlarge the clean photo only. Add the headline, logo and legal copy afterward as vector type and logo files. Lamar and OUTFRONT both accept native Illustrator and InDesign files and print-ready PDFs, and vector type stays sharp at any size.
- Check the enlarged file at 100% around the product: label text, logo edges, seams, and any texture the upscaler sharpened into a pattern that is not on the real product.
- If the label must be exact, composite the real packshot into the render at board size. AI photos for packaged goods covers when to do this.
- Watch the file size. OUTFRONT’s Los Angeles bulletin at 25 ppi is about 60 megapixels, more than Topaz Gigapixel’s 56-megapixel limit in Photoshop. Ask the media owner before you build a file that large.
Design for the distance
- One idea per board. Lamar’s digital guidance says the key to effective out-of-home is brevity: one message, a strong focal point, readable fonts and contrasting colors.
- Keep words off the edges. OUTFRONT’s bulletin spec says no text within 0.5 in of the live area at 1 in = 1 ft scale, which is 6 in on the board. Lamar adds a 6 in bleed on every side of a bulletin.
- Print is CMYK, digital is RGB. OUTFRONT asks for all bulletin images in CMYK. Lamar asks for digital art in RGB, preferably sRGB, with black set to R0 G0 B0. AI renders come out in RGB, so convert print files and check your brand colors after conversion. See how to keep brand colors accurate.
- Day and night. Lamar notes that rich, bold backgrounds work better in daylight and pastel backgrounds look more vibrant at night on digital boards.
- Deadlines. OUTFRONT wants printed material at least 10 working days before the posting date.
Checklist before you send the file
- The media owner’s spec sheet for the exact unit, with its scale, resolution, bleed and safe margins.
- The approved render made again at the model’s largest size, in the widest shape it offers.
- Enlarged with a detail-preserving upscaler, and checked at 100% around the product.
- Headline, logo and legal copy set as vector type, not rendered by the image model.
- Converted to CMYK for print, or kept in sRGB for digital, with brand colors checked after conversion.
- No text inside the edge margin, and bleed added where the spec asks for it.
- For digital, a 1400 x 400 (or the owner’s size) JPG, with no animation unless the owner allows it.
Questions people also ask
- What DPI should a billboard file be?
- At full size, 12.5 to 25 pixels per inch, depending on the media owner. Lamar sets up bulletins at about 12.5 ppi and posters at 18. OUTFRONT’s Los Angeles bulletin spec asks for 25. Files are usually built to scale, such as 1/2 inch = 1 foot at 300 ppi, which works out to the same number.
- What size is a digital billboard file?
- Usually 1400 x 400 pixels for a 14 x 48 foot digital bulletin, per Lamar’s auto-scale template and OAAA’s standard formats. OAAA lists 1800 x 600 for large digital bulletins and 840 x 400 for digital posters. Lamar takes JPG, BMP or GIF files in RGB and does not accept animated GIFs.
- Do I have to say a billboard image was made with AI?
- The Lamar and OUTFRONT spec sheets we checked do not ask for it. Some laws can, depending on where the ad runs and what it shows; Google’s ad help pages point to rules in the EU, India and New York. Do you need to label AI images in ads covers the platform rules and links to the legal guides.
Where Overs fits
Overs can include a billboard in a set’s deliverables and render it on the image model you choose. Preparing the print file, from enlarging to the media owner’s spec to converting to CMYK, happens in your own design tools.
Free for 40 photos a month. The AI that makes the photos is billed separately, on your own key, with no markup from Overs.
Sources
- Lamar Graphics: Print Templates (bulletin and poster production resolution)
- Lamar Graphics: Digital Templates (auto-scale and actual pixel sizes)
- OUTFRONT: Bulletin production spec, Los Angeles unit 61287-B (revised 25 August 2026)
- OUTFRONT: Production specs (New York digital transit)
- OAAA: Out of Home Advertising Today (2016), standard OOH and DOOH formats
- NCBI Bookshelf (StatPearls): Evaluation of Visual Acuity
- Adobe Photoshop help: Enhance image quality with Generative Upscale (updated 21 November 2025)
- Google AI for Developers: Nano Banana image generation (sizes by aspect ratio)
- OpenAI: Image generation guide (size options)