Alpha channel in computer graphics implies transparency. One can control transparency level by selecting values fr om 0 % to 100% depending on how much of the image you want to show. Alpha channel contains some information about the image apart from color. All RGB images contain 3 main color channels, but some images contain an additional channel that represents opacity. The problem appears when a certain image containing the alpha channel cannot be rendered by the software application that does not recognize the alpha channel. Or you may just want to remove the alpha channel to avoid transparency. Removing the alpha channel can be done with the help of ImageConverter Plus. Open the folder wh ere Image Converter Plus is installed and find file icp.ini. Open this file in a simple text editor (for instance notepad.exe). Go to the end of the file and add the following two lines:
[HDR]IgnoreAlphaChannel=1
This means that alpha channel will be ignored when viewing or processing images in HDR format (HDRI Radiance). In many cases using this option is the only way to convert images correctly. Same procedure can be performed on other image formats supporting the alpha channel.