Hi @meryem_gz
I ran some tests to see if I could offer some help with this Experimental feature. There is not a lot in the way of parameters to play with.
To play with this more, I added a New Screen and selected the Landscape print template. I dropped a Gallery on the Screen and linked it to a SharePoint List.
I was not able to get my Gallery to show with as much white space as you have, but things definitely depended on the Width set for the Gallery. I also played with the Margin setting and the Size setting. Margin seems to help.
ContentBytes: PDF(Gallery2,{Orientation:"Landscape",ExpandContainers: true, Margin:"5mm", Size:PaperSize.A4})
I don't know if this will help you or not, but you could try setting the Width of the Gallery to a variable. Right before running your "SendEmailV2" code runs, change the varGalleryWidth variable to a larger or smaller value. After the "SendEmailV2" code runs, set the varGalleryWidth back to it's original value.
Check the pdf that was generated. While testing, include the varGalleryWidth in you email.
Hopefully with some trial and error, you can find something that works.
-Mark
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