This has been fixed.

All completed :)

ported to https://invent.kde.org/education/gcompris/-/issues/42

yes, but as we have nothing new in the branch, it will wait until next release :)

Screenshots updated on the fastlane folder (on master and 2.0 branches) and on the playstore.

I'll take care of that.

Thank you!

Looks good to me, I tested a few activities and didn't noticed any bug. There are still some png (but not big files so we won't gain much by converting them to webp):
src/activities/hangman/resource/fog.png
src/activities/memory-sound/resource/Tux_mute.png
src/activities/memory-sound/resource/Tux_play.png
src/core/resource/aboutkde.png
src/core/resource/arrow.png
src/core/resource/gcompris-icon.png
src/core/resource/gcompris.png
src/core/resource/star.png

All done (or almost, still waiting for the erase images from Karl, who is still working on it).

I already started working on it, but it takes time as I also replace some photos in some activities (currently in categorization especially, it's a bit long but soon finished).
In most cases, resizing not lossless with quality 90 is OK and already saves some space. For other cases like erase activity images, if we replace those with higher resolution images, they'll probably need to be compressed with quality 50 or 40 to have an acceptable size.

For lang, we go from 59.7Mo to 40.2Mo with a conversion of all png with no loss (magick $f -quality 100 -define webp:lossless=true $f.webp), so for me, it's a go :).

The issue in Number sequence was fixed long ago now (commit a768009e5e0644410614ab677677bf57f056722e ).
The issue in enumerate was fixed in commit d5fd8e5239fd8cf72dbff1d793e99f3d3737172b.

Fixed in 416b267b30f9cf31ee9ecd96fa271e006396212a

I agree this is a good idea, we should add something to indicate when there is a filter.
I'll start thinking about it and propose something soon.