X-Cart forums - image detail and upload max filesize

Hi
As you may notice, I am new at the forum, and I feel a bit lost amidst so many information.Well, I need your help as my web master is on vacations and I urgently need to fix the look of the store.My problem is the following:
Yesterday, I wrote to qualiteam support requesting the following help :

Quote:

I am having a hard time to add images in my store with the configuration
settings that I would like.
I manage to setup thumbnail to a specific size of 200x 200 pixels.
Now, I face two problems:
1 - when I click in the thumbnail to load the page that details the product, I
would like image to be displayed in size 400x 400 pixels and not in thumbnail
size;
2- Then, I would click on the magnifier that should display image detail, which
I would like it displaying an 600x 600 pixels image.
I simply cannot change items 1 and 2 described above. I have already set "Detailed Product Images module" as below:

Display detailed images in a popup window: X

Switch detailed images in a popup window without page reloading (using the
dynamic image loading): X

However, I am not able to post the image once the maximum allowed size is 150b.> I request the support to explaim me where and how do I change the size of images
to be displayed in items 1 and 2 of my questioning (the page that shows the > product and the image detail) and also so I can upload imagen details larger
than 150b.

today I received the following reply

Quote:

There are no specified settings in X-Cart admin area for any product images except for product thumbnails, which is located in the General Settings > Appearance Options.
However, you can alter the X-Cart code to set the desired images dimensions manually. Here is the corresponding templates for product images below:

------------------------
/skin1/main/popup_image_js.js
In this template you may define the 600 x 600 dimensions for detailed pop-up image
------------------------
/skin1/customer/main/product.tpl
Here you may define the 400x 400 image size on product detailed page
------------------------

Additionally, the max allowed upload file size is set in the "upload_max_filesize" PHP variable. So to be able to upload images larger than 150b please ask your hosting administrators to increase the "upload_max_filesize" to the necessary value.

It so happens that I don't understand much about these files and I fear to change wrongly something .For example, in the file "product.tpl" I don't know where I change so the size image be 400 x 400 px.I just don't know which variable I have to change there so image is displayed in size 400 x 400 px.Also, I don't know in which file I should look for and the location of file "upload_max_filesize" PHP variable" to change it

Could anyone help me ?
I thank you in advance for any help:oops: .
All the best