A program that uses bitmaps can be slower than one that does not. The first time a bitmap is displayed, it must be transferred from the server to the client. The bitmap is then placed in a memory cache on the client so that it doesn't have to be downloaded again. However, network messages travel between client and server regardless of whether the bitmap has already been downloaded to the client.
Bitmap download performance can be enhanced via the W$BITMAP library routine WBITMAP-LOAD process. Setting the WBITMAP-LOAD parameter FLAGS to WBITMAP-NO-DOWNLOAD optimizes bitmap handling. When WBITMAP-NO-DOWNLOAD is used, the server assumes that the bitmap is already in the client's cache directory and that the client can successfully load the bitmap. The server need not wait for a result code from the client that the bitmap is successfully loaded. For more information about W$BITMAP and the WBITMAP-LOAD function, refer to the appendix "Library Routines" in ACUCOBOL-GT Appendices.
Using .jpg files instead of .bmp files can also improve system performance, because .jpg files are compressed and therefore are smaller and transfer more quickly over the network.