Generally, you cannot convert any JPEG files directly to APK. However, some apps can use images or even videos to create rich and sometimes animated wallpapers for Android devices. These are generated as APKs, i.e. apps that are installed and run in the device to replace the wallpaper. So jpg to apk is not a conversion per se.
Convert JPEG bitmap image format to Google Android application package.
We found one software available in the database for this conversion.
Microsoft Windows software - convert jpg to apk on Windows
An Android wallpaper design app
Convert from jpg file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.