Dayum! OK, go here:
http://www.suzukicycles.org/index.htmlClick on the "All Suzuki Models" tab.
Click on the "Suzuki GS Series" tab.
In this section, click on the following tabs to view the bikes/info:
"Suzuki GS550M Katana"
"Suzuki GS650G Katana"
"Suzuki GS750S Katana"
"Suzuki GS1000S Katana"
When you're done looking at those, go back to the All Models tab and click on "Suzuki GSX Series" tab and click on the following:
"Suzuki GSX250S Katana"
"Suzuki GSX400S Katana"
"Suzuki GSX750S Katana"
"Suzuki GSX1000S Katana"
"Suzuki GSX1100S Katana"
Most of the images that come up on these pages are clickable for larger versions.
In a nutshell, the 250, 400, early 750, 1000 & 1100 models all look pretty much the same. The late 750 has a different front fairing with hideaway headlight that when down, makes the fairing look smooth, otherwise, its general shape is the same. It also has a monoshock rear suspension and a sleeker tail section. The 550 has typical original style Katana tank & seat (with a better looking tail than the 1000's style, IMHO), but no front fairing (ie; a naked Katana). The 650 looks pretty much the same as the 550, but has shaft final drive instead of chain.