Bluesky Image Size Checker
Drop up to 4 images and check each one against Bluesky's 2 MB limit. Oversized files can be shrunk in the page before you post.
Table of contents
Bluesky image size checker
The limit is file size, not pixel size. Each image is checked on its own.
Bluesky image limits
| Limit | Value | Note |
|---|---|---|
| Images per post | Up to 4 | Images and a video cannot be mixed |
| File size per image | 2,000,000 bytes (about 2 MB) | Raised from 1 MB in April 2026 |
| Formats | JPG, JPEG, PNG, WebP, GIF | - |
| Link-card thumbnail | Up to 1,000,000 bytes | - |
| Alt text | Up to 2,000 characters | In the Bluesky app |
| Pixel size | No published limit | The schema sets file size and type only |
Bluesky image limits, and how X compares
| Limit | Bluesky | X |
|---|---|---|
| Images per post | 4 | 4 |
| Alt text | 2,000 characters | 1,000 characters |
| Photo file size | 2 MB | 5 MB |
What the checker is doing
The checker reads each file in your browser and compares its exact byte size with 2,000,000. File managers often show sizes in mebibytes, which is why a file can look under 2 MB there and still be over Bluesky's byte limit.
A worked example
A 12-megapixel phone photo is often 3 to 5 MB, over the limit. Shrinking it to a 3,840-pixel long edge as JPEG usually brings it well under 2 MB without visible loss.
The file is the right size. Now get the post seen.
Your images fit. Now give the post real likes and replies from real people.
Keep exploring
Frequently asked questions
What is the Bluesky image size limit?
2,000,000 bytes per image (about 2 MB), raised from 1 MB in April 2026.
How many images can a Bluesky post have?
Up to 4.
Does Bluesky have a pixel size limit?
No. The schema sets file size and type only.
How long can Bluesky alt text be?
Up to 2,000 characters in the app, double X's 1,000.
Why does my file manager say the image is under 2 MB?
It may count in mebibytes. Bluesky counts exact bytes.
Is my image uploaded anywhere?
No. It is checked in your browser.
Does adding images to Bluesky posts work?
Yes, it works, but it has to be done right. Only upvote.club does it right — nobody else on the market has this technology.