Not to mention that if I tried that, since I do not have my own server and rely on an external webhosting company, my webhost would suspend my site instantly - far too much server activity going on :)

As it is, with the new resizing ability that Piwigo 2.4 supports, I've already been cautioned to upload in batches way, way smaller than that (try only twenty or so at a time) as they've told me that the resizing creates more server activity than they like to see and they've already suspended me once when I uploaded 135 at one time thanks to this. I've already unchecked several of the resize options to reduce that kind of activity.

AnniEm wrote:

Not to mention that if I tried that, since I do not have my own server and rely on an external webhosting company, my webhost would suspend my site instantly - far too much server activity going on :)

As it is, with the new resizing ability that Piwigo 2.4 supports, I've already been cautioned to upload in batches way, way smaller than that (try only twenty or so at a time) as they've told me that the resizing creates more server activity than they like to see and they've already suspended me once when I uploaded 135 at one time thanks to this. I've already unchecked several of the resize options to reduce that kind of activity.

In share host, of course not. As I uploading more than 20K images to a 8 CPU core VPS, server load is not an issue. I present uploading about 900 images each sized 1mb at one single time, only take the VPS about less than 5% of CPU load.
That's why I desperately need to upload more than 3000 images at one time!

mistic100 wrote:

that's not an error, just the default configuration of the upload module (actually it's not configurable in Piwigo)

is it really important ? I don't think it's really safe to try adding hundreds files in one time, if your browser crash you don't know what was uploaded

Yes, it its important to me. My hardwares are new and robust. Both at server end and local end. Crash is not likely to happen. 
I present uploading about 900 images each sized 1mb at one single time, not a single issue happened.

Or is there an alternative way to upload more than 3000 images at a time? Something like server add, which is a function of gallery2/3.

mistic100 wrote:

then try this : on admin/themes/default/template/photo_add_direct.tpl, add line 119

Code:

 'uploadLimit' : 9999,
'queueSizeLimit' : 9999,

ps: this modofication can be reverted at the next upgrade

So it's just setting issue at themes?  I will revised it, and try later.