There are a few ways to remove part of an image in Photoshop. One way is to use the Eraser tool.
With the Eraser tool selected, simply click and drag over the area you want to remove. The pixels will be erased to transparency. You can also use the Pen tool to create a path around the area you want to remove and then use the Erase to Path command under the Edit menu.
If you want to remove a certain color from an image, you can use the Select Color Range command under the Select menu. This will bring up a dialog box where you can click on the color you want to remove.
Photoshop will then select all pixels that are similar to that color. You can then inverse the selection and delete the selected pixels.
Another way to remove part of an image is to use a layer mask. With a layer mask, you can paint over the area you want to remove with black or white.
Black will hide the layer and white will reveal it. You can also use a gradient on a layer mask to fade out an image.
Conclusion:
There are a few different ways that you can remove part of an image in Photoshop. Depending on what you want to achieve, you can either use the Eraser tool, the Pen tool, or a layer mask. Each method has its own advantages and disadvantages, so be sure to experiment with each one until you find the best solution for your particular project.