Reducing image file sizes

[Terry Judd]

If you're using GraphicConverter then you probably want to use the scale
option under the size item of the picture menu. This will let you specify
both an output width and/or height and resolution. If the images are for
screen display then obviously 72 dpi is all you need. If you want print
output then 150 dpi would be an absolute minimum. I'd maybe do this in two
stages. First just set the dpi of the image to what you want - this won't
change the overall size of the image. Then proportionally resample/resize
the image to whatever your maximum width/height settings are appropriate
before saving them in whatever format is appropriate (it sounds like you'll
be using JPEG).

I guess you could do this all in Rev provided it is capable of displaying
images with the types of pixel dimensions you're talking about and you only
want screen resolution images. You'd set the filename of an image object and
query its formatted width and height. Then you'd rescale it to match your
predetermined maximum dimensions. Finally you'd export a snapshot (which
will be at 72 dpi) with your preferred level of JPEG compression. If you
want more than screen resolution then you should export them without
compression and take them back into GraphicConverter to change the
resolution without resampling (resolution item of picture menu) and then
save and compress them from there.

HTH,

Terry...


On 19/05/09 11:15 AM, "J. Landman Gay" <jacque at hyperactivesw.com> wrote:

> Terry Judd wrote:
>> There are two possible ways to go...
>> 
>> 1. resample the images to reduce the resolution
>> 2. recompress the images
>> 
>> Method one will probably only be of use if the images are already at or
>> greater than 300 dpi. You could probably resample them to as low as 200 dpi
>> while still retaining sufficient print quality.
>> 
>> Method two will probably only be really effective if the images are
>> currently uncompressed. If that's the case then saving them as max or high
>> quality JPEGs will save you a lot of space without an appreciable loss of
>> print quality.
>> 
>> Terry...
> 
> Thanks, very helpful. I think method 1 is the one that applies in this
> case, but I don't know what's involved with resampling. But see my
> answer to Brian, I'm going to explain more what this is for. Maybe I'm
> on the wrong track.