When I tried to run it, I got "This application has failed to start because jper62.dll was not found. Re-installing the application may fix the problem.".
Anyway, I found it on the web and placed in the same dir as *.exe and app lounched, but whenever I load *.png or *.jpg 'Convert' button doesnt get enabled.
*.bmp works fine
And please add the line for the dimension requirements in readme.txt, it may save some time for someone
EDIT: for the *.bmp I get unexpected result (picture seems to be a bit streched, edges cut).