I cannot but agree with BostonJoe, with respect to some sites.
About 3 years ago I was looking for a new house to rent. I found an ideal house on a real estate site (business owned and run by a Thai man). The pictures on his web page showed a new well furnished house. He took me to view the house.
Shock horror. The house apeared to be 10-15 years old. The owner of the house was there, using a water house to clean the inside of the house!! The inside the house was very dirty, in disrepair, and had zero resemblance to the pictues on the web site, apart from the shape of the rooms. The beautiful gardens and swimming poor where not there on inspection - all the plants, shrubs and grass were dead, and the pool resembled an algae haven.
Some other houses I visited at the time with some other real estate agents were not as bad, but clearly the pictures on their web sites were out of date by several years.
As for dating sites/apps - photoshop, or some similar age reversing and/or beautification apps, are extensively used.