Here's what I have settled on for maps of my own capturing:
1 follow the instructions about making a folder called "photos" (I think it was on kindleworld.blogspot)
2 each set of images gets its own subfolder there (displayed in kindle Home screen as a "book title")
3 while you can conserve kindle space by resizing to 800x600 pixels, I haven't done this unless the source image is multi-megapixel.
4 an advantage of keeping the loaded JPG map images in their full color form is that you could plug in USB kindle to friends' PC and copy the color file to them (even though kindle shows you grayscale only on the e-ink screen)
5 an alternative could be to "print to PDF" the images, one per page; then use kindle's PDF viewer. Alternatively, dropping them into a Word Doc allows you to use the amazon convert service and get a AZW fomated file back Remember that kindle does come with a crude image viewer for sets of JPG, like these maps: rotate, zoom in, for example.
Often I have used maps.yahoo.com (but I like maps.google.com for the Japanese text)