Most big sites store one upload and serve resized copies of it from a CDN. The size of the copy is written into the image URL: sometimes as a path segment, sometimes as two letters before the extension, sometimes after an = at the end. If you know where that token sits, you can edit the URL in the address bar and get the stored file instead of the thumbnail.

I measured five sites this week. Each image below was fetched with curl and its pixel size read from the file header, so these are real numbers from November 2026, not documentation. CDNs change, so check them again before you build anything on them.

Site What the page loads Edit What you get

Bluesky feed_thumbnail , 1000×750 WebP feed_fullsize 4000×3000

Mercado Libre D_Q_NP_2X_…-AB.webp , 448×448 D_NQ_NP_…-OO.jpg 1704×1919

Blogger (unlinked image) w320-h213-rw , 320×212 WebP s0 566×376 PNG

Steam ss_<hash>.600x338.jpg , 600×337 drop .600x338 1920×1080

Google Play =w1052-h592-rw , 333×592 WebP =s0 1080×1920 PNG

Bluesky: a different path prefix

An…