I am wondering so I can upload an image as a thumbnail without it getting distorted.

somewhere around 167x100
at least that's from my best estimate

The aspect ratio of a studio thumbnails is 17 : 10. That means for every 17 pixels in the horizontal direction, you have 10 pixels in the vertical direction.
The max allowed image size for studio thumbnails is 500x500, meaning you should probably be making images up to ~500x294 so that Scratch doesn't squash the the image.

The original edit of this post was incorrect. While yes, studio thumbnails are grabbed at 17:10, they are instead used at the aspect ratio 20:13. I was unable to catch this before posting my original response. To move on, the max possible image size you can upload to Scratch is 500x500, however, doing this will result in a large amount of stretching. If we want to minimize the stretching of an image, we will want to upload it at the exact aspect ratio that Scratch studio thumbnails are(20:13). But how do we get the most out of this? We get it with math. We need to first divide 20 by 13, which gives us 1.5384615385, then we divide 500 by this number, and round it up to the nearest integer, giving us 325. Meaning the largest studio thumbnail size that you can have is 500px by 325px.

I guess it’s about 400x260, I sometimes use that dimension for studio thumbnails

Clippy-Cat wrote:

The aspect ratio of a studio thumbnails is 17 : 10. That means for every 17 pixels in the horizontal direction, you have 10 pixels in the vertical direction.
The max allowed image size for studio thumbnails is 500x500, meaning you should probably be making images up to ~500x294 so that Scratch doesn't squash the the image.

Boo!

The only thing is, on a studio, the default is a distorted gray cat! When I open it in a new tab, however, it opens as not distorted, and the non-distorted image is what's 170x100 pixels! I believe the OP is trying to upload an image that won't get distorted!

Bump

500x500
https://assets.scratch.mit.edu/get_image/.%2E/c98f678a2dc900f79ec67e302752c689.png (i cat'nt use img tags)
EDIT: I forgot img

Ambigiously wrote:

500x500
https://assets.scratch.mit.edu/get_image/.%2E/c98f678a2dc900f79ec67e302752c689.png (i cat'nt use img tags)
EDIT: I forgot img

That's the maximum size of a thumbnail, however, if you upload a square image it will get distorted.

Ambigiously wrote:

500x500
https://assets.scratch.mit.edu/get_image/.%2E/c98f678a2dc900f79ec67e302752c689.png (i cat'nt use img tags)
EDIT: I forgot img

Pretty sure OP is not asking about max size, but the one that wouldn’t make it squashed/distorted.

Oh ninja’d by 16 seconds

k7e wrote:

(#9)
That's the maximum size of a thumbnail, however, if you upload a square image it will get distorted.

oh.

Boo!

There are several studios by @ScratchCat that have not distorted thumbnails! I downloaded one of the thumbnails and uploaded them into Scratch, and it actually was 170x100! For better quality, it should be 500x294 2/17 (but leaving out the 2/17 probably won't be a big deal)!