All uploaded photos are altered to conserve storage space and network transmission costs, and to conform with layouts where they will appear.
DO NOT DELETE YOUR ORIGINALS. Photo Friday does not keep the original version of your uploaded photos.
All photos are processed into two separate files: a Large (detailed) file and a Small (thumbnail) file.
With photos that started off being smaller than 600 pixels x 600 pixels in both dimensions, no resizing occurs to produce the Large file. Visitors viewing those images will see it in the original dimensions present in the source photo. Said differently, no scaling-up will occur because doing so would result in a degradation of image quality.
With photos that are larger than 600 pixels x 600 pixels in either dimension, the source image will be resized to produce the Large file, such that the Large file's greater dimension matches 600 pixels, with the other dimension adjusted proportionally.
The Small (thumbnail) file is always exactly 200 pixels wide x 200 pixels high. By default, at time of upload, a "center-cut" thumbnail (middle of the frame for portrait- or landscape-orientated photos) is made, but Members can alter that choice at any time after uploading if a different framing is preferred.
Photos that are already exactly equal in both dimension (i.e. a square), the Small file is always a resized reproduction of the whole image, with no option for an alternate "crop region" in the thumbnail.