HOW MANY PICTURES CAN I HAVE ON MY FLAT FEE MLS LISTING?
Depends on your FSBO package you purchased as to how many pictures are included - however you can always add more by adding the "Showcase" enhanced upgrade.
The max number of pictures you are allowed varies per the MLS system:


REIN (VA Beach/Hampton Rds Area) is 32 pictures,
MRIS (Northern VA - Fredericksburg Area) is 30 pictures.
WAAR  (Williamsburg Area) is 40 pictures
CAAR (Charlottesville Area) is 24 pictures.
NRV MLS (New River Valley Area) is 25 pictures.
CVR MLS (Richmond Area) is 42 pictures.
CBRAR MLS (Chesapeake Bay Rivers Association) is 46 pictures.
RV MLS (Roanoke Valley) is 30 pictures.
HRAR (Harrisonburg and Rockingham Area) is 30 pictures.
SWVAR / NRV (Montgomery and Surrounding Areas) is 25 pictures
Lynchburg is 30 pictures.

Slideshow pictures are critical to buyers - they want to see if they like the home before they sit in traffic to see your home.
If you don't have pictures of certain rooms - the buyer wonders what is wrong with that room that you are not showing it.