I was thinking of renaming every images extension to PNG but as my lap is crapped out and i am broke as hell i would have to do it on phone is there any good app on fdroid that can do it in a bulk ? Also does renaming the end from “jpg” to “png” actually change the format ? This pictures are very important to me as they have an imotionall connection to me.
On a less important is this the same for mp3’s too as i save my favourite songs in the same way as a zip file is m4a better ?
What you’re describing is just compressing in a ZIP file. Zip files are lossless, you have nothing to worry about. When you throw a JPG in a zip file, and then extract it later, you’ll get the exact identical JPG back.
You only have to worry about jpg’s lossy compression if you’re using a photo editor like Photoshop, GIMP, etc. “Compressing” it in a zip changes nothing. Moving or copying it doesn’t lose quality either.