I have just download the new version... there's not big difference...

I know i know, but you confused me when you said "link to yesterday's" but ok i have already downlaoded it thanks Antoine

Recent versions improved mostly FLV support, there may indeed not be much other differences.
At a point they improved image quality: when I compare my DVD captures made few years ago with those that I do now, I see that MPC was improved...

I thought that you used PowerDvd...

Why my images made with MPC are of inferior quality regarding yours?

Maybe the problem is in the cropping or the resizing...

No, I use WinDVD.
But I started to use it only very recently, and the image quality is actually nearly the same: it is just a little easier to make the captures as it has the advantage of being able to advance frame by frame backwards and not only forward.

The problem may indeed by due to cropping, resizing and encoding.

Avoid compressing to JPEG more than once: make captures as BMP/PNG instead of JPEG; convert to JPEG only at the end, after crop/resize. If you have a JPEG that you modify, it will have to re-encode it, so you'll lose quality.
The resize method used (depends on the program) may also give different result quality.

I use XnView, and I crop the image manually (creating a rectangle with the mouse around the image, to exclude the black borders) and after resize it without the "keep aspect ratio" (I use this function only for the first image, for see the ideal size)

And how does the image look before crop/resize? It is easy to see if quality is lost there or if it was already bad before.

In MPC, can you also check what option is selected in View -> Options -> Output -> Direct Show Video ?

Look this for example:



The first is only resized without crop, the second is cropped and resized... the one cropped has lost a bit of quality: look very well in the low part of the image near the 640x490 and the KB, it is a bit blurred, but the one without crop isn't blurred in that place...



"System Default" also in Real media video, Quick time video and Directshow audio.

They seem pretty similar to me, but it is maybe due to multiple JPEG savings, as I said?

As output mode in the options you may try "VMR7 windowed" but I am not sure that it would change much. Your pics seem already good for images coming from TV. Do you use a DVD for transferring them to the PC? Or a TV-in capture card?

I use a DVD recorder without hard disk (directly on a DVD RW).

I have just make a capture with VMR7 windowed selected:



but the quality does not improve... perhaps for you the quality is good, but for me it is not still perfect.

Anyway I will buy PowerDvd because is quite cheap.

I do not think that you can have much better from such source.
If you wish to compare, I do the same (TV->DVDRW->PC) for the "Dr. Who" series :
http://www.imcdb.org/movie_436992-Doctor-Who.html
My pics are those of episodes up to 2.00