Resizing image files for competitions can be done with simple tools already on your computer. Lightroom or another expensive tool is not required for most resizing purposes.
This guide is for Mac users. Windows users can find an equivalent guide here.
Most resizing is done for use on a web page or for projection in a presentation or competition.
This example shows how to modify the file as for use in the JCC Digital Contest:
a. Set the color space, also known as color profile, to sRGB. (Note: The color profile tells the compute how to convert the bits in memory into the proper display colors. sRGB is the most common setting for computer displays.)
b. Resize the image, to fit a 2048 wide x 1536 high box
c. Ensure the file size is less than 2Mbytes.
d. Check resolution (aka DPI. Note: this is actually only used for printing on some devices, but some competitions will specify a number.)
- If your image is in the Photos app, right-click on it and select Edit with/Preview from the menu.
- In Preview select Tools/Assign Profile…
- In the popup window, select sRGB. Your list of options may look different from this, but sRGB will be there. (Note: IEC61966-21 is the international standard that defines sRGB)
- To resize the image, select Tools/Adjust Size…
- In the popup window, make sure the following items are set:
- Fit into: Custom – lets you select the height and width that the resized image will fit in.
- Width and Height – the desired maximum dimensions
- Pixels – required size is usually given in pixels
- Resolution (aka DPI) – this usually does not make a difference, but you change change it if you like
- Scale Proportionally – check this box to ensure your image does not get squished and distorted
- Resample image – Check this so the image will achieve the desire pixel dimensions
- Notice the Resulting Size, if this is bigger than the required size, there will be a chance to change it later.
- You are now ready to save the edited image so it can be emailed or uploaded. Select File/Export…
- Enter a filename and select a location to save it. Look at the file size. Move the quality slider to the highest level you can while keeping the file size less than the maximum.
- You can double check your work, by right clicking on the saved image and selecting Get Info.
- A window like this will pop up and you can see that the dimensions, color profile and size are as desired.
- On last caution. Many email programs shrink image files by default. Make sure to select “Original Size” or “Actual Size” in your mail program before sending.