dont mind the size, if you make it bigger by the end of this scratch will say the image should be smaller, first, see inside, then right click the logo costume, click export, then go to a svg to jpg converter website [preferably convertio.co/svg-jpg/] then select the svg file you just downloaded, click download, wait, then you get a jpg download, go back to scratch, then click set studio thumbnail on the junior devs studio, then you get the thumbnail :D
creds to @wafflezforever_ [me] @nutcocoyou @FlamingoTesting