What follows below is a suggested workflow for preparing your image for competition. The rules for digital contests are necessarily strict as the software use to run the competition requires all images to be an identical size and colour space.
This is only one suggested way - as with most software applications there are several different ways you could tackle this.
We recommend making a copy of the image before you start work, just in case you make a mistake. The guidance below applies to Adobe Photoshop and Photoshop Elements, but most other image editing software will have simiilar functions.
Step 1: Image Edits
Complete any editing work on the full-size image until you are happy with it. Try not to crop the image or reduce the overall resolution of the image (number of pixels) unless you want to remove part of the image for artistic reasons.
Step 2: Save & Flatten
If you have worked on several layers, we recommend you first save a copy as a .psd file as this preserves information in all the layers should you wish to edit further in future. Having done this, flatten the image (Layer > Flatten Image).
Step 3: Resize
Resize the image via Image > Resize > Image Size (Elements) or Image > Image Size (Photoshop), making sure that the Constrain Proportions and the Resample Image boxes are ticked.
Set the width to 1600 pixels. If the height value is now greater than 1200 pixels, then set the height to 1200 (the width will now reduce). Click [OK].
Step 4: Set Canvas
Go to Image > Canvas Size and set to Pixels. In the size boxes, enter 1600 x 1200. In the Canvas Extension Colour, set black (or any other colour you wish, but black is generally regarded as best), then click [OK].
Step 5: Set Colour Space (also known as Profile) and Save
Most competitions specify that the colour profile has to be sRGB. This is regarded as the best profile for viewing on a computer or projected on a screen. If you do not send in images in the right profile, a lot of software used will just refuse to open the file, so your entry will not be seen. You can normally see the profile in use at the bottom of the screen, if not click on the small arrow and set show profile from the list.
If you need to change the colour space / profile, click Click Image > Convert to Colour Profile (Elements) or Edit > Convert to Profile (Photoshop). Select sRGB and click [OK].
Save the image by clicking File > Save As as a jpeg, setting maximum quality (12) under any name and location that you chose.
Optional alternative step to include a thin border
Some people prefer their images to have a thin border around them to clearly separate the image from the background. To do this, set the final dimensions of the image (step 3 above) slightly smaller than 1600 x 1200 so you have, say, around 50 pixels of room spare. Then go to Select > All, or use the shortcut <CTRL> + A in Photohop or Elements. Go to Edit > Stroke, set the Width to 2px and pick a colour (we suggest white is best). Select 'inside' for location, though it isn't too critical. Now complete step 4 to add a black background and set the whole thing to 1600 x 1200 px.
Your image is now ready for any of the competitions we enter. You will now have three files saved for this image: a copy of the original, a saved .psd version, preserving all edits and layers and a sized image for competitions.
Note: It's now the case that many print competitions will require a digital version of the image to be submitted. Please bear this in mind if planning a print image and again ensure a 1600 x 1200 pixel image in sRGB colourspace is available by following the guidance above.