I have successfully registered my app to open PDF files by including the following in my info.plist:
<key>CFBundleDocumentTypes</key>
<array>
<dict>
<key>CFBundleTypeName</key>
<string>PDF</string>
<key>LSHandlerRank</key>
<string>Alternate</string>
<key>LSItemContentTypes</key>
<array>
<string>com.adobe.pdf</string>
</array>
</dict>
</array>
However, I cannot seem to register my app to open any image files, I have tried to register not only for the base image UTI, but also specific types like png and jpg. Is it possible to register to open image files?