Investigate channel selection

[yrkim98]

@thao-do says that jianxu ran into issues with channel selection- he was selecting different channels of an image which appeared to still select channel 0.

@thao-do please update this ticket after you speak to jianxu

[jxchen01]

@yrkim98 Suppose I have an image with two channels. I select one model to run and then run the prediction on channel 0, everything is fine till here. Then, when I try to run the prediction on channel 1 (using the same model), I still get the prediction from channel 0, for some reason. I guess there might be some cache ...