In one sentence
The image checker reads a local file in your browser, compares its format, file size, pixel dimensions and aspect ratio with X's card image rules, and lets you crop and re-encode it to an exact 2:1, 1:1, 1.91:1 or 16:9 image.
How do I check an image?
Choose a file, pick the card type you are targeting, and read the list of checks.
- Click Choose image or drag a file onto the drop area. Try a sample image generates a 2400x1600 test picture if you just want to see the tool work.
- Pick what you are checking for:
summary_large_image(2:1),summary(1:1), a general Open Graph image (1.91:1) or aplayerposter (16:9). - Fix anything marked red. Amber items are worth fixing; blue ones are tips.
What rules does it check?
The limits X publishes for card images, plus a few practical extras.
| Check | Rule used |
|---|---|
| Format | JPG, PNG, WEBP or GIF. Animated GIFs show only the first frame. SVG and AVIF are flagged. |
| File size | Must be under 5 MB. Over 1 MB gets a note, since smaller files fetch faster. |
| Large image minimum | 300x157 pixels |
| Summary minimum | 144x144 pixels |
| Player minimum | 68,600 pixels in total (for example 262x262 or 350x196) |
| Maximum | 4096x4096 pixels |
| Ratio | Within 2% of the target counts as a match; within 10% is "close" |
These numbers are from X's developer documentation for each card type, checked in November 2026. If X changes them, the checker will be updated.
How does the crop work?
The bright window on the canvas is what the exported card keeps. Click or tap anywhere on the image to center the window there; it never slides off the edge. For large image cards a dark bar marks the lower-left area where X lays the headline over the image, so you can keep faces and text out of it.
Then pick an output width, format and quality, and press Make card image. The result appears below with its real encoded size, and the Download button saves it with the dimensions in the file name, such as card-1200x600.jpg. Upload that file to your site and point twitter:image and og:image at it.
One image or two?
Most sites use a single 1200x630 image for every platform. On X it is cropped very slightly to 2:1, which is rarely noticeable if nothing important sits at the very top or bottom. If your images carry text near the edges, export a separate 1200x600 version for twitter:image and keep the 1200x630 one for og:image. The image sizes cheat sheet lists the numbers for the other big platforms too.
Questions
Is my image uploaded?
No. The file is opened with the browser's File API, drawn on a canvas and re-encoded on your device. There is no upload endpoint on this site.
Why is the output smaller than the width I chose?
The tool never upscales past the cropped area of your original, because enlarging only adds blur and file size. If you need 1200 pixels wide, start from a larger source.
Which output format should I pick?
JPG for photos and gradients, PNG for screenshots, flat colors and text, WEBP when you want the smallest file and your other platforms accept it. All three are on X's supported list.
Does X crop images that are not 2:1?
Yes. Large image cards are shown at 2:1, so a 1200x630 image loses a few pixels from the top and bottom, and a 4:3 photo loses much more. Cropping yourself lets you decide what stays.