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What is best way to downsize jpegs for web?

Kelly Fajack , Mar 02, 2005; 01:14 p.m.

my website is to slow but i don't want to lose any quality. Any help?



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Rab Harling , Mar 02, 2005; 02:02 p.m.

I use Photoshop. Go to image size, adjust ppi to 72 and then image pixel size to either 600 pixels tall or 700 pixels wide. Then use save for web and I save at 100 quality. Thats how I do it! I too am interested in other ways...

Patrick P , Mar 02, 2005; 02:27 p.m.

Kelly, I?m assuming you are using Photoshop. Don't bother with 72dpi, when you ?save for web? it should do that for you. Just resize the image to whatever you want on you site (Image>Image Size). After you resize don?t forget to use the ?unsharpen mask? to correct the blurring cause by the resize. Then ?save for web?. Select the ?2-Up? tab on the top on the screen. This should display the original on the left and the image that is going to be saved on the right. You can see the file size on the bottom left corner of the image. Make sure you are saving a jpeg rather than gif. Now adjust the Quality until you get an acceptable level. This can be done by using the Select box ?Low, Medium, High, Very High and Maximum) or the Quality slider. The quality you save totally depends on the image. You should see the file size change as you change the image quality. Personally I don?t like my images to be over 70K. Hope this helps, Patrick

Patrick P , Mar 02, 2005; 02:29 p.m.

For some reason the single quotes were replaced with a question mark... weird.

Rick Twigg , Mar 02, 2005; 02:35 p.m.

I use Irfan View. It's easy to use and a free download. Just do an internet search on it and you'll get a download site for it.

Bill Tuthill , Mar 02, 2005; 03:12 p.m.

The following ImageMagick command outperforms Photoshop downsampling, as Bart van der Wolf shows on his website. Furthermore Photoshop creates bloated JPEG that will fill up your disk and bandwidth more quickly than better encodings. Irfanview is OK but my version doesn't allow you to select 1x1 chroma subsampling, which is mandatory for best quality. All one line, scale selectable:

convert -filter Lanczos -scale 25% -unsharp 1x3+1+.1 -quality 95 -sampling_factor 1x1 in.bmp out.jpg

Robert Dee , Mar 02, 2005; 06:51 p.m.

Heres another idea you might want to check out, and it's freeware.


I've tried the program and it is easy to use. It cuts a few more bits without effecting viewing quality that I can see.

Good luck.

Kelly Fajack , Mar 04, 2005; 10:21 a.m.

Thanks for the feedback but none of these work with mac. Are there any that do?

Emre Safak , Mar 04, 2005; 11:15 a.m.

Bill Tuthill , Mar 04, 2005; 12:32 p.m.

Cough. ImageMagick runs on Unix, and Mac X is Unix.

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