The basic requirements for PDI entries is that the files are in sRGB colourspace, JPEG format and a maximum of 1400 pixels wide and 1050 pixels high. Many entries, including some placed and winning entries, do not meet these requirements. If Christine wasn’t so accepting, they would not be a part of the competition, they would be rejected.
The PAGB and other organisations now require images to be 1600 pixels wide and 1200 pixels high. The actions on the download page include two sets to do this. Images used for external competitions are likely to need to be at this size.
There are two pdf files available for download with screenshots and instructions for resizing. These were prepared with the PAGB sizes in mind. If you are using these then when 1600 pixels is shown you need to use 1400 pixels and instead of 1200 pixels use 1050 pixels.
Resizing images for PDI competitions:.
‘How to’ prepare images for PDI competitions – Adobe Photoshop