I use text on my folder and video images. Originally I used a green text, which I later changed to white in order to make it more readable.
I use InstantTvChannel and AmazonS3. I use Photoshop for my editing. I save all my images under " Save for Web" as png files, which are less than 300KB. The original image displays as expected. The new image, one which has only the font color changed and resaved under the original name, saves and displays correctly on InstantTvChannel. I have refreshed InstantTvChannel and Roku feed numerous times each. However, my edited image does not display, in its place, I still have the old image. I have done this for both a folder and one movie image in one of my series.
To test this further, I created a second series folder using the same image and moved one of the videos from the series into this new folder. I was hoping that it would force a refresh. Once again, instead of using my new images, it uses my old images. However, these old images are no longer on my AmazonS3 account. Somehow, Roku is storing these images and refuses to permit me to update them regardless of what I try.
At this time, this is an Unpublished Channel, with one Horizontal List folder that contains, now three series folders with a subtotal of sixteen videos.
I've found in order to force the direct publisher channels to update immediatley you have to go to settings, system and software update on the roku you are testing it with. BUT you have to wait at least 15 minutes after you change the images for the update to propegate down to the channel.. and even then I have found myself waiting several hours to see the actual change..
I waited many hours and refreshed the channel many times. The images never updated regardless what I did!
It was not until I changed the names for the images that the new images finally appeared. Then I attempted to use the old name once more with the new image. It did not work, the old image reappeared. I was forced to use that new name structure.