Hello,
is it possible that there is some kind of recompression during upload files.
Few members notticed thet file on size was: 321 KB (328 942 bajtów)
in the gallery: 230.15 KB (235 678 bajtów)

how does it work?

Thanks in advance
BR
YacentY

It's generally because of the image size settings - GD opens and reprocesses the files to downsize them, add watermarks, etc.

is it possible to disable such "feature"?

As I understand it, no it can't be disabled, but you can set the maximums high enough to cover that size.

I talked to Tech Support a few weeks ago about the settings within the Gallery. If I understood them correctly...

The value of "Image Settings: Full Size Image Dimensions" is the "Maximum Picture Size".
Any uploaded picture over those dimensions will be scaled down to those maximums.

The value of "Image Settings: Medium Size Image Dimensions" is the setting where, a picture ABOVE those dimensions will use the Lightbox or Popup, but images BELOW those dimensions won't offer the option to use either one. It just displays the picture, and putting your mouse over the image doesn't change the pointer to a hotlink.

My (minimal) testing seems to confirm this. I have my Full settings at 1600 x 1200 , Medium at 800 x 600, and all the 2.5 MB digital pictures I uploaded to my Gallery are at 1600 x 1200 in the info box, whereas some small pictures confirm the Medium settings behaviour.

Note that EITHER dimension of (H x W) determines behaviour. A picture at 801 x 10, or 10 x 601, would still use the lightbox. But one at 799 x 599 does not.

Hope that helped.

RV

Yes, you basically have it right RainbowViper.

What I would generally recommend is that if you do not want your "large size" images to be downsized at all, set the full size image dimensions to something like 10000x10000. Unless you have 10K x 10K pixel images being uploaded, that should cover them.

Then the medium sized images should be set to the maximum size you want displayed on the image view page - i.e. 800x640 or 600x480, depending on your visitor's browser size, whether you have a fixed width or fluid width skin, and so on.

Finally, thumbnail dimensions should remain small so you can fit a lot on the page in the photostrip, category/album listings, and so on.

One other thing - if you have a watermark, it will still be applied to the large sized image (as I recall...I only use watermarks minimally for testing) and it will still change in size, even if it doesn't have to be resized down.

it's strange.
I didn't change any dimensions from the begining
thumbnail is 100x75, medium 400x300 and max 1024x768
the problem is that user upload file thet is 321kb on hard drive (1024x768) but in gallery is 220kb (1024x768) and the quality is much lower.
How to avoid such issue?

Umm.... I suspect that's related to what GD2 does with the image when it processes it for the Gallery. But I'll defer to any Staff that knows for sure. (Brandon??) I'm hoping that I'm wrong, actually, since I'd really like for my digital pics to be displayed at their full potential.

And thank you for the additional info, Brandon. I didn't know you could set the maximum that high. I may go bump mine up quite a bit so I can get the pics from my camera installed into Gallery at their full size.

RV