I'm interested to see what hosted options are out there as well.
If you're willing to consider alternatives, take a look at Greenshot. It's a free and open source local program that takes a screenshot which allows you to edit it directly and copy the image to clipboard without saving.
It includes the ability to add text, blur out parts, crop, draw arrows. Just press print screen to capture an image.
I would never use a soft touch car wash. At best it's going to put small micro scratches in the paint. At worst it's going to put actual scratches in the paint.
Some good recommendations in this thread. You should give the following a try.