In the following examples, at the top of each is the full frame (suitably shrunk down) used in the comparison, with a 250 pixel wide detail from the frame underneath. The left side is from the PAL DVD. The image was captured digitally from the disc, scaled up from its native 720 by 576 resolution to 1,024 by 576 (to present in the 16:9 aspect ratio), and then, in order to be comparable to the Blu-ray version, from that to 1,920 by 1,080. The detail is from that last scaled version, and has not been rescaled again. The right side is from the Australian Blu-ray. This has not been scaled at all.

Different applications were used to capture the two frames, so I am not normally comfortable comparing the colour between the two, merely the detail and sharpness. For those visitors from NTSC lands, generally the PAL DVD is just a touch sharper than the NTSC DVD.

Good luck with making out any detail at all with the DVD:

Note the fact that you can actually see the actor's irises and the small gap in his front teeth with the Blu-ray, but not the DVD:

With the Blu-ray, you at least have half a chance of making out the brand of the guitar:

Blu-ray allows this facial expression to be seen in all its goofiness:

This actor has textured lips, like a real person. This fact is not evident from the DVD: