Apologies, I misunderstood the request!
I'm not sure this is presently possible with Retool. You may need to send it off to an external service to achieve that. I thought something like this may help (and it still may, but beyond my skillset. Note utils.getDataByObjectURL() is what transforms your blob/file to base64), but apparently manipulating base64 is better left server-side or with a library.
Maybe try reading the exif data directly and see if it's geocoded (although Retool may be stripping the data for privacy reasons) with exif-js since Retool can import JS libraries. For mobile & app-specific instructions, see below.
Thanks for the post, though - I took this on because I realized I'm going to need to know how to do it in the near future - albeit, i'm okay with storing the data alongside and not within the image.