What kind of TV screen do you have? Is it a normal 4x3 or a 16x9 wide screen?
You have to look at your images file size both ways: pixels x pixels and side x side.
Most compact cameras offer 4x3 images, just now some come to the market offering 16x9 porportions. DSRL cameras tend to offer also 3x2 to match the print papper sizze, as 10x15cm.
Pixel wise: DVD format is NTSC 720x480 and PAL 720x576 for 4x3 screens. For the wide you have to check, as I don't know it by heart.
I don't know how Nerovision does it, but there are software packages that adjust from your file size to the DVD size, but probably with no change in the porpotions. Others require you to offer them the right image size (pixels).
You can also have the adjustment made with black bars and the full image or a crop.
Look also to you TV set: does it changes to the right format (4x3, 16x9, letter box) by itself or requires you to do it?
Did you use any zoom facility?
You have to work it out and try to find the answer, these are just some points you may look at.