When you wish to enter an image into the club projected image assignment you have to resize it so that it is a maximum of 2000 pixels on the longest side, 

To do this.

1  Open the image in Photoshop.

2  Select image and then image size from the menubar and the following dialog box will open.     

3  Ensure that the resample box is clicked. (Its in the light grey area.)

4  In whichever side ( Width or Height ) is longest change the units to pixels and put 2000 into the number area. I have indicated these areas by highlighting them in light grey.

5  Click on OK.

6  Save the image using a new Filename so that it does not overwrite the file.