The problem is that the JPEG viewers used in most (if not all) DVD players use a very simple algorithm for resampling still images to the DVD player native resolution. Unfortunately, the built-in DVD player in the Beovision-7 also suffers from that limitation. I have also an upscaling Sony DVD recorder and it's not better in that aspect. Good downsampling is not trivial and requires a computationally expensive algorithm.
The workaround is to resample the images using a computer program that uses a better algorithm to 640x480 (NTSC) or 768x576 (PAL) pixels and to prepare a disk with the resampled pictures (keep your originals intact).
The steps are:
1- Download and install the IrfanView free image processing program.
2- Open the original image.
3- In the menu, select Image, then Resize/Resample.
4- Set the vertical resolution to 480 (NTSC) or 576 (PAL). Select the Lanczos filter (that's the key to obtain good results). Make tests with both resolutions.
5- Save the image to a new name in JPEG format with the 90 quality setting.
6- IrfanView has a batch mode that allows the conversion of several pictures in one run.
7- Burn a disk (CD or DVD) and put the new images.You will see a substantial improvement in quality. Put a few original images and you will see the differences.
When I was using the Sony DVD recorder with my MX-5000, the limitations of the downsampling algorithm were not as noticeable, but with a high definition TV, this is different.
Good luck!
Jean