Select the size of your banner. Check with the forum in which you will place the banner to ensure that it is not too small or large. Banners typically appear between 728 x 90 pixels and 728 x 200 pixels.
Establish the size of your banner. Open Photoshop and select “New” under the "File" menu, which prompts you to select the size of your project. Ensure that “pixels” display on the pull-down menus on the right, then enter the respective length and height. Make the resolution between 72 and 300.
Add an image to the background of your banner. You can either create one from scratch or import images that you own. To import an image, save it as a PDF, select "Import," then "PDF" under the "File" menu, and select the image from where you saved it. Alternately, you can open the picture as a new document in Photoshop, use the magic wand to select the field outside of the image, click “Inverse” under the “Select” menu, select "Copy" under the "Edit" menu, return to your banner project, and select "Paste" from the "Edit" menu.
Re-size the image to fit your banner. If you already deselected it, either click “Undo” under the “Edit” menu, or revert back to your last action before deselecting it in the “History” window. Then, select “Transform” under the “Edit” menu to re-size the image appropriately.
Edit your banner. Edit it manually using the tools from the "Tools" window and apply filters from the "Filters" menu. Add text by using the “Text” tool, which automatically creates a new text layer.
Save your new banner. First, you must flatten the image. Click on the right-pointer arrow just below the "x" button in the "Layers" window and select "Flatten Image" from the menu. Then, check your target forum for upload size limits and ensure that your banner fits those constraints. Also, check the forum for accepted file types. The most commonly accepted file types are .jpeg, .png, and .gif. Finally, save your new banner, and you're done.