Improve the thumbnail service to support compression and WEBP

[dhruvkb]

Fixes

Fixes #531 by @zackkrida

Description

This PR replaces willnorris/imageproxy with h2non/imaginary, a faster, more feature-rich and more highly-rated library for image manipulations over HTTP. This library allows us to compress thumbnails and reduce bytes.

Now, we can control the dimensions of the thumbnail and the amount of compression using env vars (while also allowing the URL query params full_size and compressed override the defaults if needed).

To spark joy, this PR adds API documentation for the thumbnail endpoints (both audio and video) with all query params documented.

Testing Instructions

0. Check out the PR and fetch thumbnails for some audio/image files. They should load normally.
1. Play with the full_size and compressed query params.

• With full_size set to 'true', the image should be larger.
• With full_size set to 'false', the image will be smaller.
• Compression is by default set to the opposite of full_size, but can be overridden with the compressed param.

Stats

Here are some randomly sampled cases.

Full-size no-compression	Full-size compression	Thumbnail no-compression	Thumbnail compression
307 kB	84.1 kB	223 kB	30.6 kB
385 kB	96.1 kB	279 kB	39.9 kB
387 kB	108 kB	278 kB	42.9 kB

Checklist

• My pull request has a descriptive title (not a vague title like Update index.md).
• My pull request targets the default branch of the repository (main) or a parent feature branch.
• My commit messages follow best practices.
• My code follows the established code style of the repository.
• I added or updated tests for the changes I made (if applicable).
• I added or updated documentation (if applicable).
• I tried running the project locally and verified that there are no visible errors.

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[sarayourfriend]

This is such a great find Dhruv! I'm excited to review this tomorrow 🙂

[zackkrida]

Really exciting and a significant change. Can't wait to investigate this more.

[AetherUnbound]

This looks great! It sees quite fast too, which is rad. There aren't any pngs in the sample data to test with, but the JPEGs all look good 🙂 I have a few comments about logging

[zackkrida]

I'll test this soon, just want to note that we make sure to manually visually diff a few thumbnails against their current, production counterparts, to check for noteworthy quality differences or any other issues.

The new library looks great! It would be an excellent enhancement to figure out how to serve webp images in the future.

[dhruvkb]

@zackkrida the h2non/imaginary service is capable of converting images sent to it to webp as well, if we send a type param in the request. I'll run some tests with that and see if that can further cut down the size.

[dhruvkb]

Some more stats:

Thumnail compressed	Thumbnail compressed WEBP
30.5 kB	19.2 kB
29.0 kB	16.9 kB
36.4 kB	22.6 kB

With compression and WEBP, we can reduce the size even more than the already compressed thumbnails.

[dhruvkb]

This converts JPG and PNG to WEBP if the Accept header contains it. Otherwise the format stays as it is. This is to prevent issues with Safari which before Big Sur, preferentially requests PNG. JPG images become quite large if converted to PNG.

[sarayourfriend]

Looks really good! Just a few things to clean up/short-cut requests. This is really awesome though.

[sarayourfriend]

LGTM! Tested locally and it works great.

Along with the full_size test, can you add unit tests for the serializer and the validate method specifically?

[sarayourfriend]

LGTM, just curious about the release issue, whether we'll need to build an image ourselves from the latest code?

[dhruvkb]

Just noting that the process of building and hosting a custom image is being worked out in a separate PR, #641.

[AetherUnbound]

Thanks for making those logging changes! I hope you get a response soon on the build issue, but if nothing else it's good to know we have another option.