Before an image is submitted to competition it needs to meed the size requirement for that competition, usually 768 x 1024 pixels. Also, the image file may need to be less than a certain size. So how do you get your image to fit these size and dimensions There are several tools available in image editing software, and which ones you use depends upon how you want the final image to look.
More information can be found in the PSA Image Resizing Guide.
The first element to consider is the maximum image dimensions allowed for the competition. According to the PSA, the limit for most international exhibitions is 1024 pixels wide by 768 pixels high. This does not mean that your image must fit these dimensions exactly, rather that the size of the longer side of your image must fit within the corresponding number. For example:
- Landscape orientation, 683 px high by 1024 px wide - good
- Landscape orientation, 600 px high by 800px wide - good
- Landscape orientation, 300 px high by 1200 px wide - bad (too wide)
- Portrait orientation, 768 px high by 500 px wide - good
- Portrait orientation, 800px by 500 px wide - bad (too high)
Looking at item #2, you'll see that the image fits the guidelines by being completely within the required dimensions. However, you might want to reconsider using a size that is much smaller than the maximum since your image might not be displayed at its best. That does *not* mean that you should "scale up" your image. Using software to increase the image's size will result in degradation.
Changing Your Image Size
The first thing to do is start with the largest, highest quality image that you have. Just about any fairly modern digital camera will create an image that is well beyond the competition requirements (A 10mp Canon 40D creates jpeg images that are 2592 x 3888 pixels).
The next step should be to adjust your image, except sharpening, still without considering the final size. Perform all your cropping, rotating, color adjustments, etc. now.
Finally, you're ready to resize your image. Your editing software will typically have a "Resize" or "Scale" menu option, probably under the "Edit" main menu selection.
The image on the left is from the Gimp, the right image is from Photoshop Elements. Note the similarities- both allow you to select the width & height in pixels, and both have an option to preserve the aspect ratio. You'll want to preserve the aspect ratio by checking "Constrain Proportions" in PSE or making sure the chain link is "linked" for Gimp (click on it to switch). This allows you to change one dimension and have the other dimension adjusted automatically.
Simply change the width or height to fit the competition guideline. If the other value is still too large, lower it and the first will decrease proportionally.
Now you can apply sharpening if you like. This should always be the last step in your process.
Pixels Per Inch and Image Quality
For projected images, you do not need to increase the Pixels Per Inch value. 72 is quite sufficient for this purpose.
Likewise, though it may seem illogical, increasing the Image Quality will not have a noticable effect and may quickly cause your image to exceed the file size limit. Keeping the quality around 85 - 90 percent (Gimp) or 10 (PSE) is fine for projected images.
File Size Limits
The competition may enforce a limit on the size of the final JPEG image. The limit for LPA competitions is currently 4MB, others may be 1MB or as little as 850KB. Knowing the size before the file is saved can be difficult. Photoshop Elements provides an indicator as you adjust the JPEG quality right before saving. Generally, any image that is within 768 x 1024 pixels, at 90% (or "10") quality will be around 1MB or so. If you save your file and find that it's a bit too large, simply reduce the quality a little. For the human eye, the difference between 85% and 90%, or between "9" and "10" is imperceptible.
LPA and S4C Notes
For LPA and S4C competitions, the image size limit is 1024px high by 1024px wide. This does not mean that your image must be square, only that your image's longer dimension must be no more than 1024 pixels wide. This provides a couple of advantages.
- You no longer need to check both dimensions. If the longer dimension is within the 1024px limit, clearly so is the shorter.
- Portrait images are no longer at a visual disadvantage to Landscape images. Both image types can now be displayed at the same size.
For more information, Google "resizing digital images." You'll find a wealth of information. A few good links are: