Unfortunately, it's a common problem.
Firstly, the TV must have the capability to display JPEGs. Not many do unless fairly recent. (Sorry if that's self-evident, I'm not trying to teach you to suck eggs!)
Secondly, the directory structure on the card must be exactly correct for both the camera and the TV. So if you simply stick a load of images onto the card, as-is, they will almost certainly not be 'seen' by the TV. It may well report 'No card found' or similar.
If I may suggest a procedure for the future:
a) Take a few 'dummy' photos with the card in the camera.
b) Remove the card, put it in a card reader and note *exactly* where the dummy images are on the card. Often, they will be in a directory folder called DCIM, but this does vary from camera to camera.
c) Now copy any JPEGs you wish to display from the PC onto the card, ensuring that they appear inside the DCIM folder (or whatever it's called). d) Avoid using sub-directories. They may - or may not - be 'seen' by the TV.
e) If you wish, you can delete the 'dummy' photos, but it's best to do that in the camera, not via the card reader.
f) Don't be surprised if the images seem too wide when viewed on the TV (this happens on most but not all TVs, DVD recorders, etc. This is a limitation of the JPEG display circuitry in the unit. If it's a problem, it can be resolved by changing the aspect ratio of all the images so that the width is reduced by 7% (i.e. to only 93% of their original width) /before/ copying them onto the card. This can be done - as a batch -using a suitable batch-processing programme such as Faststone's Image Resizer. HTH.