Social image sizes are the most copied and least checked advice on the internet. Many guides still say a YouTube thumbnail is 1280 × 720, and that is not what YouTube's own page says today. We read the official YouTube pages on 21 October 2026, ran our Instagram and YouTube resizers on three test images, and measured the files they produce. This guide separates what the platforms state from what is only common practice.
YouTube: what the official pages say
These are the figures YouTube Help gave on 21 October 2026. We checked each page twice. YouTube can change them, so confirm on the source pages (thumbnails and channel branding) before an important upload.
| Image | Recommended | Minimum | Limit |
|---|---|---|---|
| Video thumbnail | 3840 × 2160 px, 16:9 | 640 px wide | 50 MB on desktop, 2 MB on mobile |
| Shorts thumbnail | 2160 × 3840 px, 9:16 | – | 50 MB on desktop |
| Channel banner | 2560 × 1440 px | 2048 × 1152 px, 16:9 | 6 MB |
| Profile picture | Renders at 98 × 98 px | – | 15 MB |
Two things differ from the usual advice. The recommended thumbnail is 3840 × 2160, not 1280 × 720, which is nine times as many pixels. And the 2 MB limit applies to the mobile upload; on desktop it is 50 MB. Our YouTube Thumbnail Resizer offers 1280 × 720 and 1920 × 1080, so for the full recommendation you would start from a 4K canvas yourself.
Will the file fit the limit? What we measured
We exported three of our own images as JPEG at 92% quality, which is where the YouTube Thumbnail Resizer starts, at the three thumbnail sizes:
| Source image | 1280 × 720 | 1920 × 1080 | 3840 × 2160 |
|---|---|---|---|
| Flat graphic (a blog cover) | 85 KB | 140 KB | 330 KB |
| UI screenshot | 111 KB | 189 KB | 461 KB |
| Product photo | 158 KB | 294 KB | 786 KB |
Nine times the pixels cost only four to five times the bytes, and every file was far below 2 MB. The caveat is that our sources are simple or were enlarged to reach 4K. A genuinely detailed 4K photo can be several times bigger, so for a mobile upload, check the file size. If it exceeds 2 MB, the YouTube Thumbnail Resizer lowers the JPEG quality until it fits, and the Image Compressor can do the same for any file.
The banner safe area
A channel banner is shown very differently on a TV, a desktop and a phone, and YouTube gives a single area that is always visible: 1235 × 338 px at the minimum banner size of 2048 × 1152. That is 60% of the banner width and 29% of the height, so only about 18% of the banner's area is guaranteed. Put your name, logo and any text inside it. The rest is background that some devices crop. If you work at the recommended 2560 × 1440, scale the safe area by the same factor (1.25) to about 1544 × 423 px, which is our arithmetic and not a figure from YouTube.
Instagram: what is solid and what is uncertain
Instagram's official wording is harder to pin down. Its photo help page has long said posts are shown at up to 1080 px wide, with supported shapes running from landscape (1.91:1) to portrait (4:5). More recent guides say the supported range now extends to 3:4, which matches the profile grid moving to tall tiles. At the time of writing we could not confirm the page's current wording, and guides disagree, so we recommend this approach: make the image 1080 px wide, treat 4:5 as safe (it works under either version), and check 3:4 against Instagram's help page before depending on it. These are the sizes the Instagram Resizer exports:
| Format | Size | Shape | Flat graphic | UI screenshot | Product photo |
|---|---|---|---|---|---|
| Portrait post | 1080 × 1350 | 4:5 | 89 KB | 107 KB | 164 KB |
| Tall post | 1080 × 1440 | 3:4 | 90 KB | 108 KB | 165 KB |
| Square post | 1080 × 1080 | 1:1 | 82 KB | 97 KB | 155 KB |
| Landscape post | 1080 × 566 | 1.91:1 | 65 KB | 72 KB | 66 KB |
| Story or Reel | 1080 × 1920 | 9:16 | 96 KB | 113 KB | 173 KB |
Every export was a JPEG between 65 and 173 KB. The story and Reel size is the one widely used by guides rather than one we could confirm on an official page. At these file sizes platforms still recompress what you upload, so a sharp, correctly sized original is the best protection.
What gets cropped when the shape changes
If the profile grid shows posts as 3:4 tiles, each post is centre-cropped to that shape there. The share of your picture that survives (arithmetic, no stretching):
| Post shape | Share kept in a 3:4 tile |
|---|---|
| 3:4 (1080 × 1440) | 100% |
| 4:5 (1080 × 1350) | 94% |
| 1:1 (1080 × 1080) | 75% |
| 9:16 (1080 × 1920) | 75% |
| 1.91:1 (1080 × 566) | 39% |
A landscape post loses most of its width in the grid, so keep the subject in the centre of any image you will also see there. In the resizer, Fit decides the trade-off: “contain” keeps the whole picture and fills the gaps with a blurred or solid background, while “cover” fills the frame and crops. The full tables for other shapes are in our aspect ratio guide.
Step by step
- Pick the tool: Instagram Resizer, YouTube Thumbnail Resizer, or the general Image Resizer for any exact size.
- Add your image, choose the size preset and a fit (cover to fill and crop, contain to keep everything).
- For covers, drag the picture so the subject sits where it will stay visible.
- Check the file size shown, and download the JPEG.
- For a size outside the presets, such as a 2560 × 1440 banner, use the Image Resizer with your own dimensions, and the Crop Image tool to set the shape first.
These tools run in your browser, so your images are not uploaded. To shrink a finished file further, see our compression guide.
What we did not check
We did not re-verify Instagram's current help wording, Reels or Stories rules from an official page, or other platforms. The three test images are our own simple graphics, a screenshot and one sample photo, so file sizes for a detailed photograph will be larger. Platforms revise their specs, so treat the dates in this guide as part of the data and re-check the official pages before a launch.
