If the other options fail you, try other search engines, like yahoo, ask or bing, because a lot of them turn up different results when searching the same thing. Just using the big search engines has been more than enough for me. With Pintrest, try to target specific tags, like hair color, eye color, or specific articles of clothing until something sticks out with you, then look for similarly tagged objects.
If you're looking for inspiration, it's really hard to come by; static images can only take you so far. You might want to look up some different forms of media on streaming sites- animes, movies, television shows, manga, whatever- and really broaden your horizons. If you need some suggestions for where to begin, well, there are threads for those. Some really unique personalities and asthetic designs can come from places you least expect them!
However, if you're just looking for pictures to stick on profiles...
There are pros and cons to using any method, including real life pictures. Sometimes, finding a picture actually helps to kickstart a character, or can give your partners a better idea of the nature of the person you're trying to convey, more than all the detail in the world. Some people may use a few different pictures to get a composite look, or just as a reference to a certain feature.
And I say this as someone who LIVES for descriptive writing: sometimes, the detail gets overwhelming, and people end up losing what you're trying to accomplish; they end up interpreting it completely differently and lose your vision of it. And if you're in a jump-in, where there might not be a full CS needed, are you going to go on and on, disrupting the flow of your character's entrance to describe what they look like?
I tend to stay away from custom character art for my personal reasons, but one thing I can say about it is that it's a slow and difficult process, especially when you have something very specific in mind, so why not use the photos as a stopgap in the meantime? I know plenty of people, even artists, who do that.
Plus, descriptive writing just might not be someone's strong point or style. I would much rather have a picture to go off of rather than a confused or half-baked description of a person. I also choose pictures to help a partner who may have trouble visualising my descriptions. It works both ways.
We're not here to tell people how things must be done or that one way is bad or wrong. Some people just have a preference for visual images, while others have a preference for text descriptions. Either are valid and have their advantages and their limitations. There are plenty of reasons why someone chooses a reference picture from the internet, not one of which is laziness or trying to stunt the others' imagination. It is actually the opposite. It's research into a character, it's a step up to help the imagination.
These picture websites are great resources to look up some ideas of how to make a character, but that's probably all they should be used for. I really support that idea, that's how I've designed a lot of characters, but I've never put anything I've found on a profile for a character, because I would be presenting inaccurate information to a reader, (and conflicting information is never good,) or outright stealing the appearance of another character/person.
If all else fails, less is more. Begin with bare-bones, minimalist descriptions, and the personality of the character. You can base a lot of their appearance on that alone; beauty is only skin deep.
Jump-Ins and Chat Roleplays, don't have time for introductions. It's meant to be fast-paced; are you going to break the flow by inserting images? Is there really time or interest in reading all of that, when people are interested in speed and silly dialogue?