These photos have been altered to give them a different appearance. You could use a simple "filter" to create a similar effect, but for best results I 'prepare' the photo... Some of the originals are good photos and some are rejects because of exposure or focus problems. The rejects are often less challenging because they are already somewhat 'prepared.'
To prepare, usually I lighten and/or darken some of the already light and dark areas, increase or decrease contrast, and blur the entire photo or parts of the photo. Occasionally I increase the saturation of parts of the photo or use another filter (such as 'cutout' or 'cartoon') before I add the watercolor filter. I may even add an oil painting filter before or after the watercolor filter. I have lots to learn about Digital Art, there is much more to Digital Art than this, but these are pretty.