How to attain the correct KB size of an image.

[choronr]

In using Photoshop, I'm trying to determine how to attain the KB size of an image. Some sites allow you to post your image but limit the KB size to 512. As you then must decrease your image size but don't know by how much until you 'save' the image. More times then not, you end up having to go through this process a number of times until you get close to the 512KB size.

Is there a scale or formula somewhere where one could learn how to attain the correct KB size and avoid the 'hit or miss' exercise. Example: My image is 2400 x 864 pixels. This is 675.3KB size. What size in pixels must the image be in order to attain 512KB?

[Kadri]

It does not only depends on the image size.
The easiest way i know in Photoshop is in the "Save for Web" menu.
You get another window.
Choose JPG from the right above and play with the settings
while you can look at the left lower part how big the resulting image will be.

[choronr]

It does not only depends on the image size.
The easiest way i know in Photoshop is in the "Save for Web" menu.
You get another window.
Choose JPG from the right above and play with the settings
while you can look at the left lower part how big the resulting image will be.

Thanks Kadri; but the trouble is, you won't know what the KB number is until you save - and, if it is yet too large or too small, you have to start all over.

[Kadri]

Not sure if i understand it correctly ...
The way i wrote above shows it already without saving the file.
It shows the image KB size in the left lower corner in the new window.
It is not the "Save as" menu.
It is the "Save for Web" menu what i am speaking about.
This one:

[attachimg=1]

[choronr]

OK Kadri, I've got it. Thank you again for your patience. I appreciate your help.

[Kadri]

You're welcome.

[choronr]

Hi Kadri,

One more thing, I noted that about 1/3 of the image (right side) is cut off when saving for the web. There was no slider to allow one to see the rest of the image. Does this mean that all one will see is 1/3 of the image when saved? I have not saved the image as yet.

[Dune]

Use Irfanview; you can easily save for web and see the size before saving. Sliding the compression until you have the right amount of kB if you like. Irfanview is free and VERY handy.

[Kadri]

The image isn't cut off.
On the lower left side you can see a percentage (above "Preview") that you can change to see the full image or to zoom in.
That is only for preview purpose. The image is saved fully.

As Ulco said other programs does have similar options too.
In XnView there is an "Export" option that does the same for example.
XnView is free too.

[choronr]

Use Irfanview; you can easily save for web and see the size before saving. Sliding the compression until you have the right amount of kB if you like. Irfanview is free and VERY handy.

Thank you Ulco. I have Irfanview but haven't used it in awhile. Must get the plug-in for 'Save to Web'.

[choronr]

The image isn't cut off.
On the lower left side you can see a percentage (above "Preview") that you can change to see the full image or to zoom in.
That is only for preview purpose. The image is saved fully.

As Ulco said other programs does have similar options too.
In XnView there is an "Export" option that does the same for example.
XnView is free too.

Thank you once again Kadri. I think I need a new pair of glasses.

[Oshyan]

Use XnView, better interface than Irfanview IMO, and no plugin needed for web save; just use Export, same functionality as Photoshop, with even some features PS doesn't support (like adjusting the JPG subsampling factor; I like to use 1x1, 1x1, 1x1 for best quality).

- Oshyan

[choronr]

Oshyan, thank you. Kadri also recommended this. Been looking for better ways of saving the final. Appreciate this