I have just uploaded 100 new images through ftp. Only about 20 are shown as thumbs and normal pictures. I have the classic red X in the corner and the filename. Zenphoto can show the full image and exif info, but not the pictures. I only have one other album which looks fine. I have recently re-installed zenphoti including database.

This is usually due to images whose dimensions are too large for the server you are using. Did you review the troubleshooting guide?

Hello , and in advance, sorry for my english.

I have some similar problems, and often read that the image's size are responsible of the troubles.
I do a test, and the result is quite amazing : the biggest photos are shown, the smaller aren't.
And I think it isn't a question of Ko, but the size of the width of the image. under 600 pixels, the image is not shown §
Take a look at my test gallery : http://alerions.free.fr/Gallerie/index.php?album=Gib2009
The last pictures are different sizes of the same original ; you wll be able to test yourself, and may be find another explanation, or confirm mine.

I think you got a permissions issue. Safari's activity windows notes "forbidden" for those images. So check the permission on the albums folder.

It is not the file size of the image that makes the difference, it is the dimensions.

Jpeg pictures compress to various differnig amounts. But when the image is expanded for processing it will take up memory based on its dimensions. The amount of memory will be **3.

Sorry for my insistence, but what is disturbing me is that the display seems to be the wrong way :
the largest picture (in file size or dimensions) IS shown while the smallest is NOT.
Exemple :
http://alerions.free.fr/Gallerie/index.php?album=Gib2009&image=aler03_d.jpg is 500x680 and 96 Ko => NOT shown
http://alerions.free.fr/Gallerie/index.php?album=Gib2009&image=aler03_g.jpg is 650x884 and 163 Ko =====> SHOWN

I don't understand what can explain that small pictures can't be displayed !

Best regards,
PB

Well, there are a few things you should do.

First, you are running on a pretty old version of zenphoto. Use the nightly build.
Second, you are using a custom theme. Try one of the distributed themes.
Third, review your CGI logs for errors.

There are any number of things which can cause images not to be processed. When it is happening only to some images it is usually an issue with the particular images. Have you reviewed the troubleshooting guide?