plots: expand supported images extensions

[pared]

After #6431 we support rendering of JPEG, GIF, PNG images.
We could expand this list by other images types that browsers support.

Related:
treeverse/dvc.org#2839 (comment)

[dberenbaum]

I think we can expand as needed by users.

[jorgeorpinel]

SVG? Maybe TIFF? Uncompressed bitmaps? I'd ask CV people.

[blakeNaccarato]

I think that SVG is perhaps a good first addition, as plotting libraries can output that and they are often a bit smaller than PNGs. Having at least one vector format and one raster format would be a good goal. Probably not a first priority, but it would be nice!

[daavoo]

Unless I am missing something, this would only need to update:

https://github.com/iterative/dvc/blob/d7152e360e4770c54645e84ca9b690389d60dd07/dvc/repo/plots/__init__.py#L556

[blakeNaccarato]

I hope my addition of only SVG makes sense for now, as it is the first vector format to be added to the list of supported plots, and it is a common output format of Python plotting libraries. I'm sure that other figure extensions could be added as needed in the future. That would probably entail opening a new issue (or commenting on this one?) and specifically referencing the desired additional format. Contributing further extensions would look a lot like the changes I made in the linked PR as well as the documentation changes in the mentioned issue above, over at https://github.com/iterative/dvc.org.

Thanks for the help in reviewing/merging!