What things make the file is corrupted and not readable as an image file?! if the sd card is read-only, this prevent that I able to take a copy from it??!
What do you mean by image is corrupted ?
If it's an installation issue with WIn32DiskImager, here's my experience:
I just installed Raspbian on an SD Card this morning and I got an error too but went to Raspbian official doc and found Etcher which work really well and even have a portable version !
Here's the release page of their Github, you'll find what you need: Github Balena.io