How the resizer works
The resizer draws your image onto a canvas at the exact size you pick and lets you download the result. It runs on your device: the image is never uploaded to Postocial or anyone else, and nothing is kept once you close the page.
- Crop to fill scales the image until it covers the whole frame, keeps the center and trims what doesn’t fit. Use it for photos.
- Fit with background keeps the whole image and fills the empty space with a color you choose. Use it for logos, screenshots and products that must not be cut.
- PNG or JPG: JPG makes much smaller files for photos, PNG keeps text and flat graphics crisp. JPG has no transparency, so the background color fills transparent areas.
Image sizes by network
| Network | First size in the menu | Sizes | Details |
|---|---|---|---|
| Feed post, square: 1080 × 1080 | 6 | Instagram image resizer | |
| Feed post, square: 1080 × 1080 | 6 | Facebook image resizer | |
| TikTok | Photo post image: 1080 × 1920 | 2 | TikTok image resizer |
| Link post image: 1200 × 627 | 4 | LinkedIn image resizer | |
| YouTube | Video thumbnail: 3840 × 2160 | 5 | YouTube image resizer |
| X | Post image, square: 1080 × 1080 | 8 | X image resizer |
| Threads | Feed image / carousel item: 1440 × 1920 | 2 | Threads image resizer |
| Standard image Pin / carousel Pin card: 1000 × 1500 | 4 | Pinterest image resizer | |
| Google Business Profile | Post or profile photo: 720 × 720 | 1 | Google Business Profile image resizer |
| Bluesky | Avatar: 1000 × 1000 | 2 | Bluesky image resizer |
| Mastodon | Avatar: 400 × 400 | 2 | Mastodon image resizer |
| Community banner (moderators): 1080 × 128 | 1 | Reddit image resizer | |
| Tumblr | Post image: 540 × 810 | 4 | Tumblr image resizer |
| Telegram | Story photo posted by a bot: 1080 × 1920 | 1 | Telegram image resizer |
File size limits to keep in mind
The right dimensions are half the job. Networks also cap the file size, and an image over the cap fails to upload or gets compressed:
- Instagram: feed and story images through the API must be JPEG, up to 8 MB.
- Facebook: Page photos through the Graph API can be up to 4 MB, and Meta suggests keeping PNGs to about 1 MB.
- X: up to four images per post, each up to 5 MB; profile photos under 2 MB.
- LinkedIn: Page logos and cover images up to 3 MB.
- YouTube: thumbnails up to 50 MB from a desktop or 2 MB from a phone; channel banners 6 MB or smaller.
- Pinterest: Pin images up to 20 MB on desktop or 32 MB in the app.
- Google Business Profile: JPG or PNG between 10 KB and 5 MB.
- Bluesky: avatar and banner up to 1 MB each.
- Threads: JPEG or PNG up to 8 MB.
- TikTok: photo post images in JPEG or WebP, up to 20 MB each.
- Mastodon: post images up to 16 MB; avatar and header up to 8 MB.
- Tumblr: post images up to 20 MB; avatar and header up to 10 MB.
- Telegram: photos sent through the Bot API up to 10 MB.
Tips for sharp results
- Start with an image at least as large as the size you need. Enlarging a small image can’t add detail, so it turns soft.
- Keep faces, logos and text away from the edges of profile pictures, covers and banners, which networks crop on some screens.
- Download photos as JPG and graphics with text as PNG.
- Check the preview. If Crop to fill cuts off something important, switch to Fit with background.