How to handle new image/video format of iOS on Linux laptop?

I transfered my images from my iPhone to my Linux laptop (debian 10) by running the following command: sudo dmesg|grep SerialNumber: Then in file browser, I pressed Ctrl+L then write: afc://IPHONE_SRIAL_NUMBER This gave me access to my iphone and I could copy all the images to my PC. When I checked the transferred files, I didn't actually find files. I found that each image is located in a folder. Folders have different extensions (.HEIC, .JPG, .MOV). The images in these folders have poor quality and are small-sized. Not what I used to find when exporting my files to PC. I tried converting the .HEIC folders to .jpg by running this command for file in *.heic; do heif-convert $file ${file/%.heic/.jpg}; done but I got the message : Could not read HEIF file: Invalid input: No 'ftyp' box How can I handle these folders to get normal images and vidoes out of them? I don't want to loose my images or my images' quality.