Is designing only with images a good idea for old systems? [on hold]

I know most of you are designers. I'm suppose to work on an old IDE to create a software. Now I'd like to make the application look good. Since I can't use CSS, BOOTSTRAP or any other web frameworks that helps in designing UI, I thought I'd go with the following approach... Design everything I want outside of the software then do a print screen. I'll import the image in the IDE and use it as a background for my design.

Now I don't know much about design. Is is a good technique ? I'm noticed my images are kinda blurred when imported... Mainly it's BMP that I'm importing....

How would you proceed if you had to desing for an old IDE ?