Yes, a picture says a thousand words. And it's critical to upload photos of your exchange offer (see section on Your Photos, below).
But you ALSO need words to describe your home and highlight the key features and amenities. Both are important to give fellow community members a feeling for whether your place and YOU are a match for them.
Start with some descriptions that help give a feel for your place. Describe why your home is more than just walls and a roof. For example, your house has large windows that allow loads of natural light. Or your wifi is accessible from the back porch that overlooks a lake, forest or lush green backyard.
Don’t forget the details! If you have an in-house washer/dryer, add it in as an amenity. Done any upgrades or renovations within the past few years? Mention them.
Let your profile viewers know about things they may not even know to ask. For example, tell them your house doesn't have air conditioning, but that's because there are only a few days a year it is ever needed (and for those days, fans are sufficient). Or let them know that in the winter, the meadow behind your house becomes a pond that attracts all types of waterfowl.
Potential swap mates would likely want to know that your duplex is walking distance to local coffee shops, antique stores or museums...so say it in your home description. And if you're willing to allow pets in your home, mention that your home is pet-friendly for dogs or cats and that the backyard is spacious or there's a local dog park nearby.
Remember, you want people to read your listing and feel like they want to be where you are! So put yourself in THEIR mindset as you write.
Lastly, a tip on length: don't make your listing too short (a 1- or 2-sentence home description doesn't engender trust), but you don't want to write a book either.