Whether you are uploading your own custom range, or adding content to your website, every image must be resized to size.
Uploading an image which is massively too large will cause the image to load slow and take up valuable bandwidth even though you may resize it in the editor.
If you upload a custom range and the product image size isnt right, the image will become skewed and blurry.
When you load your own custom range, images must be resized to 400 high x 400 pixels wide - a perfect square so it loads fast and the right shape.
This is an example of a 400x400 image. Its resized to a perfect square, low in size yet still good quality.
If you need a free batch image resizing tool, I would suggest using FastStone Photo Resizer. This free software can be downloaded here: http://www.faststone.org/
Guide on using FastStone Photo Resizer:
1. Open FastStone Photo Resizer and drop and drag your files to the Input list and click Use Advanced Options.
2. On the Resize Tab, make sure you have these settings
3. On the Canvas Tab, make sure you have these settings and click OK
4. Set your Output Folder - where the resized images will be saved and click Convert
Uploading Images for Content
When you load images onto your website, make sure its to size in pixels, otherwise if the image is too large it may go off your web page, cause issues when loading and other problems.
Most page sizes are between 600 - 900 pixels wide so resize images to fit within your web page area.