Yup, I just download a bunch of images, show or send it to a sighted friend/relative for reviewing. They tell me which ones can go in the project.

But, in last couple of years, images in my assignments and projects were just excel charts and diagrams lol. So for those, only beginning I use to ask if those images look fine, later turns out, I got confident. If you know what diagram or chart you are looking for and you select it correctly, If you copy the diagram as image, and you don't mess up the data in excel, your diagram is pretty much gonna come out as you expect it to.

I usually ask a friend!

You can't do it independently. You can either ask a sighted person you know or use a service like Be My Eyes or Aira.

What about powerpoint presentations?

Have someone else help that’s the only solution to this one. I always hate these things and if I have to do it I’ll get someone to help or get around to it by explaining and seeing if I can get it waived or exempted.