Generally speaking, you cannot convert any image file type directly to APK. However, some apps can use images or even videos to create rich and sometimes animated wallpapers for Androids. These are generated as APKs, ie. programs that are installed and run in the device to replace the wallpaper.
Which means that jpeg to apk conversion is really not a conversion per se, more of generating a simple Android app that contains the image your video you import in to.Open JPEG file Open APK file
An Android wallpaper design app