[IPOL discuss] Vignette image compression in archive

[Bertrand Kerautret]

Dear All,
In the test of the demonstration 68, I see that the vignette images of 
the archive gallery appear with low quality in comparison to the 
original ones.
In particular it is visible on image representing a distance map in gray 
scale format. For instance you can see it here:
http://dev.ipol.im/~kerautre/ipol_demo/68/archive/
The vignette images look as if it was near binary images while the 
original are more in grayscale.
The format used is png, and by testing it with jpeg it looks better (see 
last archive).
Did there is a simple way to define the vignette quality in the app.py 
file ? (else it is not a problem we can use jpeg i think)
Thank for your help.
All the best.
Bertrand