About JPG to AVIF
Rather than asking you to adapt a general-purpose app, JPG to AVIF is organised around JPEG image files. It accepts an image file in the source format, works to converts one representation into another with a clearly labelled result, and makes a converted image file ready to download available when sharing images with a service that needs a particular format.
JPEG compatibility is considered in the conversion or processing result. Taken together, these details make JPG to AVIF suitable for sharing images with a service that needs a particular format.