One thing I should have mentioned about using your own images - there's lots of images in the client/images that never get used in the channel, so there's no need to create them. You can see the necessary images by looking at the example theme I posted. In general, it's all the "square" images, the "Logo" images, and the "Slice" images. If you want to change the colors used, you'll need a colors.xml file
Here's the complete list:
folder_square.jpg
livestream_square.jpg
loopall_square.jpg
media_square.jpg
music_square.jpg
nowplaying_square.jpg
photos_square.jpg
playall_square.jpg
playnew_square.jpg
settings_square.jpg
shuffleall_square.jpg
streams_square.jpg
videos_square.jpg
media_Logo_Overhang_HD.png
media_Logo_Overhang_SD43.png
music_Logo_Overhang_HD.png
music_Logo_Overhang_SD43.png
photo_Logo_Overhang_HD.png
photo_Logo_Overhang_SD43.png
settings_Logo_Overhang_HD.png
settings_Logo_Overhang_SD43.png
streams_Logo_Overhang_HD.png
streams_Logo_Overhang_SD43.png
video_Logo_Overhang_HD.png
video_Logo_Overhang_SD43.png
Overhang_BackgroundSlice_HD.png
Overhang_BackgroundSlice_SD43.png
colors.xml - optional
As I mentioned before, you can use JPEGs, PNGs, or GIFs for any image, but the file name has to match the above list for the channel to be able to find it. You don't have to have a colors.xml file and you don't need _SD43 images if you're only ever planning on using this on an HD TV. Likewise you don't need the _HD images if you're only planning on using this on an SD TV. If you want to create a theme for everyone, you'll want to create both sets of images (and test them out by putting your box in both SD and HD modes - it doesn't matter if your TV is SD and your box is in HD mode and vice versa).
The colors shown in my example theme are the only ones that are changed from their defaults. There's lots of other colors (mostly text colors) that could be changed. You'll want to download the developer's documentation if you're interested.
-JT
Roku Community Streaming Expert
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