Which sim is this for? AF is the native texture format for the old Flight Shop/Aircraft Factory design application. For FS98 or CFS1 you can open them & convert them back after repainting with ConvR8. http://www.mnwright.btinternet.co.uk/index.htm

Many of these files have been converted to BMP format for FS2000 & the later M$ sims. These can be opened by renaming the files with the BMP file extension. They can be converted if necessary with BMP2000. They would need to be saved in the appropriate FS texture format - then renamed with their original .*AF file extensions to display in the sim.