How can I tell Asset Catalog (.xcassets) to use the Same Image for Multiple Image Wells?
You can right click on the .xcassets file and choose 'Show in Finder'. Go to the 'Image.launchimage' folder and open the Contents.json file in a text editor. Here you can see that unassigned slots don't contain an "filename". You can add this manually. For example change the following:
{ "orientation" : "landscape", "idiom" : "ipad", "extent" : "full-screen", "minimum-system-version" : "7.0", "scale" : "2x"}Into:
{ "orientation" : "landscape", "idiom" : "ipad", "extent" : "full-screen", "minimum-system-version" : "7.0", "filename" : "Default-Landscape@2x~ipad.png", "scale" : "2x"}Now safe the file, and voila!