At the moment the standard dimensions for the Club Projected Image Competition is 1920 x 1080 pixels.

Anything larger / smaller than these dimensions will be automatically resized and quality may suffer because of it. 

for Adobe Photoshop,

Open your image RAW, JPEG, etc in Photoshop.

Need to convert to sRGB Colourspace. Select Edit->Convert To Profile

And ensure Destination is sRGB

To resize image Select Image > Image Size. Ensure pixels is selected.

Change the resolution from the default (usually 240) to 72.

Ensure constrained proportions is enabled

As a general rule irrespective of if image is landscape or portrait orientated enter 1080 for the height

Check that the width doesn’t exceed 1920. If it does you need to instead set the width to 1920

or Adobe Lightroom.

To resize on Lightroom you do this at the time of Export

Select image to Export then Select File->Export

First locate the File Settings

And select sRGB for Colour Space

No locate the Image Sizing section

Set Resolution

Set size to 1080 Pixels

Now you need to set the edge. If the  image is Landscape you select Short Edge and if Portrait Long Edge