Thanks for the review and the kind words :)

There is nothing the 'buyer' needs to be aware of. The app is completely free and all features are available for you to try before you purchase the upgrade for high resolution images. It seems very childish to me to rate one star because of one insignificant feature you would've liked and two other reasons that don't really have much to do with the app. 1) There are differences between operating systems. iOS doesn't have the extended save file dialog like macOS. For iOS I picked a single file format to keep things simple. In our email exchange (assuming that was you) I at first assumed I picked a format with transparency support, but then I corrected myself because the format is actually jpeg. Nowhere else do I claim the background should be transparent.2) This is not something I can remedy. In edit mode I had to put in significant effort to make it interactive. For the final render it is up to the user how long the rendering should be (pick a lower resolution or disable anti-aliasing to make it faster). In the end the speed is still limited to the hardware of the device, so if this is really important to you, you need to buy a faster device.3) I'm sorry to hear Apple is making it difficult for you to get a refund. This has nothing to do with the app. Payment and refunds are done 100% by Apple. Also, in this case you easily could've tried the app before spending money on the upgrade.