X-Com Image Extractor does a lousy job. Some images it does right, if you select the correct palette. Palettes for UFOPedia images are very confusing.
It splits spritesheets up into individual images. Falko's Tools will re-combine them into a spritesheet but before I knew about that (and any time it's offline), it was very strenuous making spritesheets by hand.
Some images it doesn't even recognize, for example if they're in a *.DAT file. Those have to be found elsewhere.
These images aren't a quick 5-minute grab. I've already put dozens of hours into assembling this image archive, and that's not counting all the time spent trying to figure out how to do it, asking others for help, and throwing my hands up in frustration and leaving it for another day. And I'm still not even done with UFO Defense images, TFTD is barely started. It's a lot of work, and it's a labor of love, that's why I want to share this archive. I don't want others to have to go through what I went through to get this stuff.
Speaking of which, if there's any variation in format you guys think would be useful to add to the archive, let me know. I want the images to be easy to pull up and use.
Also, seems like you did just that 
judging by the fact that few errors the tool has show also in your archive, for example in folder: https://www.dropbox.com/sh/d9g42iwxp92o6ou/AACKgB-kbXVII2_tRlbJqp_7a/UFO/UFOGRAPH/X1?dl=0&subfolder_nav_tracking=1
Do you know how to fix it?
