I believe your .sqlite file should be in Documents, this is the correct place for it.
You downloaded images should probably be in Caches, but you could also get away with them in documents as long as you set the "do not backup" attribute.
You can set the skip backup attribute like this:
BOOL success = [url setResourceValue: [NSNumber numberWithBool: skip]
forKey: NSURLIsExcludedFromBackupKey error: &error];