You were correct to use the "Clear" command to delete old pics... actually it formats the SD card which is what you always want to do when you put in a new card. But it's pretty easy to forget to comfirm the "Clear" command by pushing the up or down arrow to finish off the job before moving on. The "Clear" command will not clear your settings, it just formats the SD card.
From the report it looks like the only cam you have running is the K camera as a stand-alone cell cam. Is this correct? If so, did you turn off the Cuddelink radio or do you have it on and the K camera set to "Home"? Either way, the only restriction of the number of pics emailed by the camera is controlled by the "Delay" setting chosen in the camera settings... there is no CL Delay option when in stand alone-mode. Even though it makes no difference whether you leave the CL radio activated or not, it seems to me that all you will do by leaving it on is waste battery power with the CL radio running with no other camera to talk to, but I could be wrong here. A second advantage to turning off the CL radio while in stand-alone mode is that you will then get the option to email thumbnails, 1meg pics or full rez pics.
Edit.... Just looked at a picture of the K cameras and realized it doesn't have a selection slider on the PIR like the G models... It's permanently set at narrow by design, so please disregard this last paragraph! It doesn't apply!
But none of this addresses your real issue of empty pics. Most likely it is a issue in the camera, but if you have left your PIR selector down (wide sensing area) it is quite common when critters are about 10 or less from the camera to get triggers before the animal enters the frame, and depending on your delay setting, followed by a more centered pic or no second pic at all if the delay is high and the critter moves on through. The wide setting on the PIR generally won't hurt you if have a fast delay set (FAP) but can kill you if you have a long delay.
Edit.... Just looked at a picture of the K cameras and realized it doesn't have a selection slider on the PIR like the G models... It's permanently set at narrow by design, so please disregard this last paragraph! It doesn't apply!