How to not modify the original picture

[PhLinuX]

For my personal family gallery, I was running cpg1.4 then 1.5 but now, it can't run anymore. (I missed to make regular updates since 1.5)
(debian 9/php 7 : mysql type is not usable anymore and must be replaced by mysqli or pdo which is a good thing).
So I was unable to make an upgrade to 1.6.
I just installed cpg1.6 in parrallel with a new database and I'm getting back my pictures stored into a "photos" disk.
As I don't want my pictures copied elsewhere, I replaced the directory albums by a link to my photos directory (as I did with cpg 1.5)
I load the pictures into cpg via the "FTP batch load" but I noticed that my original pictures are modified.
I tried removing the cpg write access (apache2 www-data group) on original pictures but, in that case they are purely erased without any message.
Only a warning icon indicates the image doesn't exists but it is already too late.
I don't find any parameter that could avoid this problem in the cpg configuration.
May be I'm doing something wrong.
Anyone can confirm what I'm trying to do it is not possible?
Many thanks

[ron4mac]

So I was unable to make an upgrade to 1.6.

You should have been able to upgrade to 1.6.
https://forum.coppermine-gallery.net/index.php/topic,79013.0.html
Depending on the situation, you may still be able to.

[PhLinuX]

Many thanks for your reply ron4mac

I didn't find this information about upgrade via a PHP script. I'm going to try it as I didn't modify anything the original configuration. 

Regarding the size of the modified files, I respond to myself :
I finaly found that my pictures were resized because they were larger than the defined maxsize in the config. (2000px max).

Thanks again for help.
PhL

[PhLinuX]

Many thanks for your reply ron4mac

I didn't find this information about upgrade via a PHP script. I'm going to try it as I didn't modify anything the original configuration. 

Regarding the size of the modified files, I respond to myself :
I finaly found that my pictures were resized because they were larger than the defined maxsize in the config. (2000px max).

Thanks again for help.
PhL