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 ?
You have misunderstood this. Saving a file from an image editor or viewer repeatedly will degrade it. Putting a single saved file in countless zips will not.