Hi,

Is there a way to retrieve information about Photo sizes specified for my Piwigo installation - so I will be able to resize photos before uploading them?

these sizes are specified on Configuration>Options>Photo Sizes tab
Multiple Size

✔ Square     120 x 120 pixels, crop     edit
✔ Thumbnail     144 x 144 pixels     edit
XXS - tiny     240 x 240 pixels     edit
XS - extra small     432 x 324 pixels     edit
S - small     576 x 432 pixels     edit
M - medium     1080 x 1080 pixels     edit
L - large     1008 x 756 pixels     edit
XL - extra large     1224 x 918 pixels     edit
XXL - huge     1656 x 1242 pixels     edit