How to scale only a bottom side of image? I made a photo of picture with distortion between top and bottom sides. I want to scale or resize only one bottom side to remove distortion. What means could do it or what easy program can do this? I do not know specific terms how to explain better.
You can use Photoshop.
Select your image, and Right Click → Free Transform and then Right Click → Distort
Now drag your edges from the corners and tweak until you are happy with the output.
You can also use Filter → Lens Correction with the Custom settings to edit the perspective distortion. (For more complex images it may be better to use the more manual method.)
You obviously have something like this:
And you want this:
You can fix it with perspective transformation tool. It's in all serious photo editing programs, not only in Photoshop. The next screenshot shows it in Krita. There it's included to G'mic filter collection:
If you search for perspective image correction you will find free online services and free software which can do it. An example: