🐛 Bug: Architecture diagram in README.md renders incorrectly when using dark mode

[guillaume-troadec]

Instructions To Reproduce the 🐛 Bug:

1. Enable dark mode on your web browser
2. View the DETR architecture diagram in README.md
3. Observe that it is transparent and we cannot see important details :(

Example

Expected behaviour:

Image renders white, as opposed to transparently

Example

Environment:

Using dark mode on Firefox (although I've tested this on other browsers and it has the same issue)

Suggestion: Replace the image with a non-transparent version from the DETR paper so that it behaves as expected when a user is using dark mode.

I'm happy to be assigned this ticket