Note that you taking a chunk of memory for the GPU here ... don't know if it will have much impact on those models with less RAM. Also, make sure you DON'T do a 'sudo apt-get upgrade' as many of the installation guides suggest, or you will likely destroy your Volumio installation.
Hey guys did I get you right, you want to improve the picture quality? If so I know the only one way which I chose for myself it's a gimbal stabilizer click here and it's really improves the quality of photos and especially videos but here the topic is not about the video as I can see. But whatever I think you should to try, maybe this will help you with your problem.