These were used, yes. I am pretty sure Windows in most of 90s used BMPs, e.g. for backgrounds and in MS Paint. [1] Also, GIF is no replacement for BMP.
Also, as far as I know even stuff like compilers (if they want to support Unicode fully) have to pull in dependencies like ICU, which because of its symbol DB weighs about 30MB.
That's another problem Win 95-era software didn't have to care about...
ICU is a problem of our own making. Computers worked with other languages all the time before Unicode. You could say the same for pretty much any modern dependency.
I'd be curious about comparing the resolution, color depth and compression levels of those images, and the bitrate/compression levels/codec of those sounds. Let's take one wallpaper. Win95 must have included a what, max 1024x768 wallpaper size? Assuming identical compression and color depths, that's still 786432 pixels total, compared to the 4K wallpapers we get today with 8294400 pixels - a larger than 10x increase. That's vastly oversimplifying, as a 10x pixel count doesn't directly translate to a 10x file size, but still, that's just for one image.
Pretty sure sounds in Win95 were MIDI, which aren't even actual audio files.
800x600 16 bit backgrounds and 16x16 16 bit icons...
> sounds
MIDI sounds...
We're not living in 1995, anymore.