ThumbGrab

Guides

Everything we learned building a thumbnail tool

Written for people who work with thumbnails every week: how YouTube stores them, why some files are missing, how to design something that survives being shrunk to a quarter size, and what you are allowed to do with someone else's artwork.

Reference

YouTube thumbnail sizes: every file YouTube stores, and when to use each

Five files, three aspect ratios, and two of them are letterboxed. A working reference for anyone pulling thumbnails at scale.

2026-08-04 · 6 min read

Technical

Why maxresdefault is missing on some videos

It is not a bug and it is not regional. The largest thumbnail is a derivative of the source upload, and old uploads never qualified.

2026-07-28 · 5 min read

Design

Design for 320 pixels, not 1280

The canvas is 1280 wide. The impression is often 320. Everything difficult about thumbnail design lives in that gap.

2026-07-19 · 7 min read

Workflow

How to run a thumbnail teardown on a competitor channel

Collecting fifty thumbnails is easy. Turning them into a decision about your own artwork takes a method.

2026-07-08 · 8 min read

Legal

Thumbnail copyright: what you can and cannot do with someone else's image

The download is trivial. The question of what you may legally do with the file afterwards is the part worth reading.

2026-06-30 · 6 min read