The subject of image optimization always crops up during my seminars, and one of the “oh, wow!” moments for almost everyone in the audience is when I compare JPEG optimization from our beloved Photoshop and Fireworks. As everyone who has seen this knows, we get a much smaller JPEG out of Fireworks. But for those of you who have not had the chance to check this out, I wanted to document it here.
To follow along, you should find your favorite uncompressed picture, or if that’s too difficult to find, you can download my RAW image – even if you try this with a compressed JPEG, you’ll still see a dramatic difference. But the optimal workflow is to start with the highest quality possible. I always shoot in the Raw format for many reasons – not the least of which is that I get that completely uncompressed image. If you have a Raw image, you’ll first make any desired adjustments in Camera Raw and then open it in Photoshop CS4.
Save the file as a PSD, since we’ll need it in a few moments. And if you’re working with a RAW image, that means that you’re probably dealing with a rather large image size – my image is a 12 megapixel shot. For this example, I’ve scaled it down to 350 x 233. In order to get the smallest possible JPEG out of Photoshop, it is important that you do NOT try a “Save As” and select JPEG. Instead, we need to go through the “Save for Web and Devices…” process (in the File menu).