So you inherited a file with thousands of high res jpegs that need to be resized for web use, great. You could spend the week mindlessly resizing them one by one, or do it once and have Photoshop do the rest of them.
The first step is to familiarize yourself with Actions. Open any of the images you’ll need to resize in Photoshop. Go to the Windows tab at the top of Photoshop and find Actions and click it open. There are some default actions already there, but you’ll need to make your own. Click the sandwich logo in the right corner on the Actions window and click “new action” it will ask you for a name (name it something that makes sense like “image resize for web” because having a menu full of untitled-95 doesn’t help anyone) and it will start recording everything you are doing. Go up to image size and resize the image to your new specs. Once your done click the stop button in the Action window and close the image you were working on, no need to save but it doesn’t hurt if you do.
Side Note: You can use Actions for anything you regularly have to do in Photoshop, I have one set up for making multiple shape layers, one set up for masking white backgrounds, one set up for resizing to a specific size, all by just clicking one button. I would recommend messing around with a few, especially if you find you have to do something over and over on multiple files.
Back to the task at hand. Go to the File tab, and go down Scripts and then to Image Processor. This block will pop up, but don’t worry, I’ll walk you through it.
In the first block it will ask you to select a file of images to use as the source, this would be your file full of too big jpegs. In the second block you are selecting where the resized images will be saved, I usually save in the same location and it will create a folder for the new files (the folder will be called JPEG, PSD or TIFF depending on the next step). Step three is what file type output you want, for this action we are only going to be saving as jpegs, but you can also save as psd if you need to keep the layers separated. The fourth box is the most important, you select the action you want to use, remember what you named that Action?
Once you get that all filled out you click the “Run” button and go make a cup of coffee. Depending on your computer and the size of the files, this time will vary. But rest assured that it will be quicker that you opening them one by one to do it manually.