Out of memory issues

[JimiSmith]

Don't decode bitmaps when downloading them, instead stream straight to disk. This should help reduce out of memory issues.

inSampleSize should also be used when loading images so they don't fill up memory

Some additional logic will need to be implemented so we don't save corrupt / incomplete downloads.

[JimiSmith]

This has been partially addressed in commit ae7786a where inSampleSize is used to ensure that large images do not fill up all available memory when loaded. This is currently hardcoded to scale images to a maximum of 1024 by 1024