I am working on a website and need to put in a lot of images. For most images, I use photoshop. I create the correct size then export using "Save As for Web & Devices." This works great, but I need to display several small images in a grid format. What works best for me right now is to layout the images in InDesign and then export the layout as a .jpg. I realize I could use CSS to create a grid of the individual images and I also realize I could layout the document in Photoshop, however, for now I want to use InDesign.
Doing this got me thinking about the compression qualities of the different programs within CS (I am using CS4). From what I understand each program is built a bit differently. For example, the text engine in InDesign is different than the text engine in Illustrator (making working with text between the two programs seamlessly a total *****). I believe differences in the programs is the same for compression engines used to create formats like jpg? I've heard people note differences between Photoshop's Save As for Web & Devices and Ilustrator's Save As for Web & Devices so maybe that is the case? (I personally cannot tell the difference). I want to know what's underneath the hood of these programs and am having trouble finding this information.
So in short, what program does the best job optimizing images (jpg or png) for the web?
My guess is Photoshop, but this is a guess. If correct, why not InDesign or Illustrator? What compression engines do Illustrator, InDesign, and Photoshop use? Are there strengths and weaknesses? Why doesn't all the programs use the same compression engines?
I realize, in the end, if it looks good it works. But curiousity is killing me and I want a deeper answer.
I can't exactly answer this, but I can add my 2 cents. I find a considerable difference in the text when I export a 72 dpi jpg vs exporting a 300 dpi jpg and downsampling it to 72dpi in Photoshop.
Photoshops down sampled jpg comes out very punchy and I notice some extra (much lighter in color) pixels surrounding black text. Whereas InDesigns 72dpi jpg the color comes out better, but the text comes out slightly blurred and quite misaligned.
It would be nice to know what makes this difference and if you can alter the compression method in either program.
InDesign doesn't do a very good job exporting pages with placed images as JPEGs, so for something like a grid of photos you will be better off exporting a PDF/X-4, opening that in Photoshop, and saving the JPEG from there.
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