There is a possibility of adding a picture to monitoring/scheduling part of t-code RSA1. The picture that can be shown needs to be customized in table RSRADIOMON. The table holds data about user settings related to BW. A field that picture name goes is called - PICNAME (Image name for monitor/scheduler). The picture needs to be stored in table RSMIME. It attributes shall be stored in table RSMIMEATTR. Unfortunately, I cannot find any standard SAP functions to store ne pictures into these tables. However, simple ABAP report that stores any picture into these tables should not be a big thing to develop.
There is a bunch (41 pictures to be precise) of picture already stored in the system. Below I took few screenshots from the pictures available in the systems. I tried BW 74, 75 and BW4 1.0 and 2.0 in all these systems the pictures are all there.
Moreover, there is other field PICSTRETCH in the table PICNAME that allows stretching the picture over full size of part of the GUI screen.
MONITOR_MED.JPG
SAPBW_MONITOR.JPG