Collector: Make sure that you have the VESA drive is selected in the RESOURCE.CFG and not the VGA driver.

Wishbone: I just bought the whole series in the promo. I've never played any of them before, and so I was looking forward to it. I noticed something odd though. On the first screen (the shop), the image appears to be 320*200 resolution, but some of the objects (newspaper, coats, magnifying glass) are in a much higher resolution. Is this normal? Was the game always like that? I've never seen that in a 2D game before. It's not actually a problem, I just thought it looked very odd, and got curious. Also, is it a giveaway? Are all objects you can interact with in a higher resolution than the rest of the game?
[Edit]
It was plainly not so in the original. Compare this screenshot from MobyGames with this one from GOG's GK1 page. They are not exactly the same size (the GOG one is scaled up a bit), but you can still plainly see the difference. So where did these hi-res objects come from?

AstroanutDown: It's normal. This is because this version is the new one that Sierra released a bit after, optimized for newer machines with SVGA etc. You'll also notice that the menus and cursors are in higher resolution. Actually, that's pretty much all the work Sierra put into "optimizing"... As you'll see, all the cut-scenes are not redone in higher res and as a result they play out in a smaller frame! Bottom line though, this is quite normal.

Collector: The main difference between the two screenshots is that the MobyGames image is with the VGA driver without aspect correction (320x200, probably scaled to 640x400), hence it looks squished. With the VESA driver it will be 640x480.

Patryn: The truth is, Gabriel Knight 1 had indeed two resolutions at the same time. Backdrops were 320x240 and some of the items, the inventory and talking close-ups were 640x480.
The problem is, that - in my opinion - the backgrounds look worse in 640x480 because pixels are merely doubled.
That is why items look out-of-place.
Just a suggestion: Do the opposite of what Collector suggests and replace VESA.DRV with VGA.DRV in Resource.cfg and use a DOSBox graphic-filter like 2xSAI.
In my opinion this looks a lot better than pixely background and ill-fitting items.

Patryn: The truth is, Gabriel Knight 1 had indeed two resolutions at the same time. Backdrops were 320x240 and some of the items, the inventory and talking close-ups were 640x480.

The problem is, that - in my opinion - the backgrounds look worse in 640x480 because pixels are merely doubled.
That is why items look out-of-place.

Just a suggestion: Do the opposite of what Collector suggests and replace VESA.DRV with VGA.DRV in Resource.cfg and use a DOSBox graphic-filter like 2xSAI.
In my opinion this looks a lot better than pixely background and ill-fitting items.