LinkedIn 4:5 ad image: 720x900, mobile only, no side borders
LinkedIn's vertical single image ad is 4:5 at 720x900 and serves on mobile only; 1:1.91 vertical images get side borders. How to request 4:5 on Sume.
For a vertical LinkedIn single image ad, use 4:5 at 720 x 900 pixels. LinkedIn says paid vertical assets serve on mobile devices only, and that 1:1.91 vertical images get borders added to either side. On Sume, ask for aspect_ratio 4:5 instead of 720x900, because 900 is not a multiple of 16.
LinkedIn numbers are from its Help page, read 2026-10-01. Sume details are from the image docs.
What are LinkedIn's vertical limits?
The page marks 4:5 as the recommended vertical ratio and says it avoids borders.
| Field | LinkedIn value |
|---|---|
| Recommended | 4:5, 720 x 900 pixels |
| Minimum | 360 x 640 pixels |
| Maximum | 2430 x 4320 pixels |
| Serving | Paid vertical assets serve on mobile only |
| 1:1.91 vertical | Borders added to either side |
How do I request 4:5 on Sume?
The image docs say 4:5 is Instagram portrait (1080x1350), not 4:3. Pass it as aspect_ratio. GPT custom sizes need both edges multiples of 16, and 900 is not, so 720 x 900 is not a valid custom size; the ratio is the safer route. 1080 x 1350 sits inside LinkedIn's range.
What if I have a video clip, not an image?
Video filter has a crop op that takes a rectangle as fractions of the source frame: x and y in 0 to 1, width and height in 0.05 to 1. A 4:5 crop of a 16:9 frame is a width fraction of 0.45 over full height. For video ad rules see LinkedIn video ad specs.
Why does the border matter?
A border means your image does not fill the frame, so text near the edges may sit on filler. Make the file 4:5 from the start and the frame is filled.
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