ERROR ITMS-90032 "Invalid image path"

I ran into this today, as well. A quick fix for this is to:

1. go into the Xcode project > Build Phases > Copy Bundle Resources > + (add) > Add Other...
2. Navigate to [project] > Images.xcassets
3. Shift + Click to select all .png files
4. Click Open

Then try creating an Archive and uploading to the App Store. This was the only thing that worked for me.