Click on the File Menu, then Open as.
As HEX file: You can open any file and display it in the HEX viewer window.
You can see all bytes in HEX and ASCII mode of the opened file. (for advanced users)
As ASCII file: You can open any ASCII file (TXT, HTM, INI etc.) and display it as image.
As RAW file: You can open any file and try to load it as RAW image. (for advanced users, using Formats/RAW PlugIn)