Pixelmator
Replace Color Tool
Here is how you can use Pixelmator Pro to to change the color of any object in an image
Let's say you wanted to make the shirt someone is wearing a different color well the Replace Color tool can do that
Using the Replace Color Tool
Load an image in Pixelmator Pro that has an object you'd like to change the color of and then type the letter "a" on your keyboard to open Color Adjustments in the Tools Sidebar. If you scroll down to the bottom of Color Adjustments you should find the Replace Color tool or click Format in the menu bar and mouse down to Color Adjustments to find it there as shown in my illustration
The Replace Color tool has two little windows each with a color-picker eyedropper. To change the color of an object click the eyedropper on the left window and then mouse over and click anywhere in the object that you want to change the color of and you'll notice that the little window on the left is now the same color as the object you just clicked on. Now click inside the little window on the right and you will see a large number of color options so just click on any of them to change the color of your object. If you click on the right-hand windows eyedropper instead of inside the right-hand window you can then mouse over and click anywhere in your image and your object's color will be changed to the color of your image where you just clicked
If your chosen color didn't completely cover all of the object, increase the Range on the slider just below the windows or decrease it if it colored more than you wanted. The Intensity slider just below the Range slider lets yo dial back the new color incrementally so can decide how the new color blends with the old one and if you slide it back to 0% your object will revert to its original color
Here's a link to a little video I put up on YouTube that gives you a more visual depiction of how the Replace Color tool works