I am afraid I can't help you there - I am using my own image, and the check sum would be different.
I would caution about using any part of the 0.7.5 build with any later build. It is true I am using 0.9.0 firmware with the 0.8.0 build, and it works fine, but I would be very hesitant about using bzimage with a different build. Best to get you a good matching one. You might try using a different browser to download - one that is not so sure it knows best about file types. Chrome or Firefox maybe. Also - don't just click on the file name - use right mouse button and select save as.