Hi there
Welcome to THS and lots of great adventures ahead.
Based on what you wrote, it sounds like you didn’t actually accept the sit but just did a call for it? If you are feeling apprehensive strictly because of the lack of photos, you can ask the homeowner to upload some to the listing or send them to you privately. They are supposed to provide interior photos of the spaces sitters will be using, and it is not unreasonable for a sitter to want to see what their living space will be like.
There have been a couple of instances where I took sits that were really appealing for one reason or another without seeing a lot of interior photos; but I felt confident because prior sitter’s reviews noted things about the decor being nice, it being very clean,etc… It is also an intuitive thing that gets honed after doing this for so long. And the places were always great. But generally speaking, I don’t apply to sits where there aren’t photos of the living spaces.
There is talk of THS monitoring cancellations, but I recall one of the moderators on here recently stating that a HO has to notify THS of the cancellation, which means that there isn’t some system in place where cancelled sits get reported automatically and ‘investigated.’ I imagine if a sitter gets ‘reported’ numerous times for cancelling, they then take a closer look at their activity,etc…
Are there other reasons you don’t feel comfortable doing the sit? Or is it just the photos, which can easily be rectified by asking for some? If there are other things that feel off, you can certainly cancel if you have already accepted; but generally speaking, once a person commits to a sit, they should only cancel if they truly can’t do it or things come to light after accepting, like the HO making major changes to the scope of the assignment that are not acceptable to the sitter, and they would not have agreed to originally.
But ultimately you can do whatever you want and give whatever reason you want…no one can force sitters not to cancel. If you are new to this, there can be a bit of a learning curve. Choose sits carefully and trust your instinct. You don’t want to go into this thinking you always have cancellation as some sort of ‘back up’ should you change your mind, something better comes along,etc…
My best advice for choosing sits is considering what the day to day experience will be like. You want to consider the location, various elements of the home, the types of animals and their routine, the various responsibilities, and how all that gels with your personality, preferences skills,etc…because that is going to be the biggest determinant of whether you truly enjoy the experience.
It is all too easy to just focus on the location, the convenience of a sit fitting into your schedule, a house having really great amenities and the like, and people end up doing sits that aren’t a good fit for them.
trust your gut 
