Google Nexus 4 can take pictures with quality up to 8MP. If you want to change the camera quality and change picture size on Nexus 4, do as follows:
1. Open "Camera" App
2. Tap and Hold your finger on the screen, and wait to see a menu
3. Move your finger to the Settings icon and release your finger
4. Select "Picture Size"
5. Choose one of these picture sizes: QVGA, VGA, 1.3M pixels, 2Mp, 3Mp, 5Mp, 8Mp