Just tested out inkscape with 10 random 5,000 x 5,000 images embeded - save time ~5 seconds, load time ~11 seconds. Total svg file size ~200Mb. Inkscape definitely isn't a perfect piece of software, but it should be able to handle what you need

I typically use GIMP or Inkscape. Never had issues with importing lots of images into Inkscape, which is vector based, but that may depend on the resolution you import them at.

One of my favorite genera! Super charismatic

One of those rare flying crabs

Was worried my last proposal wouldn't get funded because this administration doesn't want to fund anything to do with climate change. Turns out it's going to get flagged because it uses the phrase "bee diversity"