thumbnails, making file size smaller -- why is small & large photoshop jpg same size?

Discussion in 'Web Design and Development' started by rawdawg, Jun 9, 2009.

  1. rawdawg macrumors 6502

    Joined:
    Jan 7, 2009
    Location:
    Brooklyn
    #1
    In creating thumbnails for my website I'm finding some weirdness going on.

    The thumbnails are still captures of films no larger than 720x400. So the thumbnails aren't hugely smaller but significant enough, I'm shooting for around 400 pixel width.

    I took a screen shot still capture of my poster frame and saved as a Tiff. I worked with it in photoshop and saved as a jpg (5 compression), it was 120KB. That is my full sized image. Knowing I planned on displaying it smaller on my website I also saved a resized jpg (re-sampled so it's not just smaller with larger DPI) to 200 pixel width. My main concern is making it load faster. When I select the compression 5 from the Tiff it says it's 50KB which is good. But for some reason, saving at the same compression setting, it's almost exactly the same size as the much larger version!? Not the 40KB it claims it is. Opening them both up in preview and looking at the inspector it says the larger one is 120KB and the smaller one is 40KB even though viewing their properties it says they're both the same???

    That's my first questions.

    But I went ahead and published it. So now going to my site I see my smaller thumbnail. For kicks I did a screen shot capture of it and also right-clicked and saved image. The size comes out 44KB and 42KB respectively, 3 times smaller than the original I used.

    Viewing the properties (command-I) of the original resized jpg that was 120KB is says it is and Adobe Photoshop JPEG file, the two I got from my site saved as simply JPEG files.

    Is there additional info in the Adobe Photoshop JPEG file and should I worry about purging it to make these thumbnails load faster?
     
  2. angelwatt Moderator emeritus

    angelwatt

    Joined:
    Aug 16, 2005
    Location:
    USA
    #2
    I do believe Photoshop adds extra meta data, though I don't think it effects file size by that much. You may be able to see some of the data by doing a Get Info from Preview. I can see various data about my camera when I view images from my camera in Preview for instance. I believe there are apps that can remove nonessential meta data, and Photoshop may have an option somewhere for it.
     

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