I can set the image sizes in WPSP, but I have different sizes for different devices, right?
Let’s see. On desktop I have 313×176 (that upscale on hover) on 3 columns, on iPad I have 183×103 on 3 columns, on smartphone 283×159 on 1 column (or 640×360 when horizontal). So, I’m kind of lost on what sizes I should be considering in WPSP.
Currently you can’t do that with the custom sizes.
You can use a filter to tell WPSP to use a different default size though (one of the default WP sizes). If you’d like that filter, feel free to start a topic in the WPSP forum 🙂