YouTube thumbnail sizes, and which one you actually want

Every thumbnail file YouTube generates for a video, what each is for, why the good one is often missing, and how to tell a real thumbnail from a grey placeholder.

The files

YouTube renders a fixed set of images for every upload and serves them from i.ytimg.com at predictable addresses. There is no API key and no scraping involved: the paths are the same for every video, and only the ID changes.

File	Resolution	Aspect	What it is for
`maxresdefault.jpg`	1280×720	16:9	Full HD. The only one worth using in a video or a slide.
`sddefault.jpg`	640×480	4:3	Standard definition, padded with black bars.
`hqdefault.jpg`	480×360	4:3	Always exists, for every video. Padded.
`mqdefault.jpg`	320×180	16:9	Clean 16:9, no padding. Good for a listing.
`default.jpg`	120×90	4:3	The tiny one used in sidebars.
`hq1.jpg`, `hq2.jpg`, `hq3.jpg`	480×360	4:3	Auto-captured frames from about a quarter, half and three quarters through.

The address pattern is https://i.ytimg.com/vi/VIDEO_ID/FILENAME. So the full HD thumbnail for a video whose ID is dQw4w9WgXcQ is at https://i.ytimg.com/vi/dQw4w9WgXcQ/maxresdefault.jpg.

Why the one you want is often missing

maxresdefault.jpg is generated only when the original upload was high enough resolution to justify it. Older videos, phone uploads from the early 2010s and anything re-uploaded at low quality simply do not have one. Roughly one video in nine is missing it.

When it is missing, the best remaining option is hqdefault.jpg at 480×360, but note that it is a 4:3 image with a 16:9 picture letterboxed inside it. The black bars are part of the file. Trimming them gives you a clean 480×270, which is what you actually wanted.

The trap: a missing thumbnail is not an error

This is the part that catches almost every tool that tries to do this job, and it is worth understanding even if you never write one.

When a thumbnail does not exist, YouTube does not return a plain 404 with an empty body. It returns a real, valid JPEG: a 120×90 grey square. So an ordinary <img> tag loads it perfectly happily and fires its success event. A tool built around "did the image fail to load?" concludes that every size exists and offers you five downloads that are all the same grey rectangle.

The only reliable approach is to fetch the bytes and measure them, check the status code, and check the dimensions, because either alone can mislead. The one legitimate 120×90 file is default.jpg, which would be condemned by a size check on its own.

Our tool probes all eight addresses before showing you anything, and lists only what is really there. If you see six results rather than eight, the other two were never generated.

Thumbnails are not frames

A thumbnail is a cover image. The uploader chose or designed it, and it need not appear anywhere in the video at all.

The hq1–hq3 files are the exception: those are genuinely auto-captured stills from roughly 25%, 50% and 75% of the runtime. They are low resolution and you do not get to choose the moment, but they are real frames.

If you need a specific moment at a usable size, a thumbnail is the wrong tool entirely, step to the frame and capture it instead.

Picking a format when you save

YouTube serves these as JPEG. Anything you export to is a conversion from that, so:

Keep the original JPG when you are just re-sharing it. Any re-encode

costs a little quality for no benefit.

PNG if the image is going into an editor. It cannot recover detail

already lost, but it avoids adding a second round of compression on top.

WebP if it is going on a web page. Around 30% smaller than JPEG at the

same visual quality.

What you are allowed to do with them

The thumbnail belongs to whoever made the video, and downloading it does not change that. Using one for reference, criticism, commentary or a mock-up is ordinary. Republishing it as your own work, or putting it on something you sell, is not.