File size not reducing when changing image size

The DPI for screen reading is 72DPI for Apple MAC and 96DPI for PC 300DPI is used for print purposes

when you create an image for the web you should save in either JPG or PNG format and set the compression ratio to whatever quality you find acceptable PNG is a later format than JPG and therefore gives better results generally, although if quality is not so important JPG can be made smaller.

Basic rule is the smaller the file - the lower quality the image.

One technique used on the web is to have a small low quality image that works as a link to an second higher quality larger image which acts as a pop-up, (this is what is seen in the magnified images used on Amazon and other similar sites using PHP, Java Etc)

joshman108 said:

I have a 16 mg image, 4500x3000. I resized all the way down to 100x100 and the file size won't change from 12.4 or so.

The file in question contains a huge blob (~12 MB) of textual metadata (see Extensible Metadata Platform) embedded into the file after the actual image data. It begins with

Code:

http://ns.adobe.com/xap/1.0/ <?xpacket begin= ...

That metadata is not image data and its size does not change regardless of how you change your image. The tools that you used to resize the images carefully preserve that metadata, which is why your files never go below ~12 MB in size.

Load your images into any editor and issue a "Save As..." command into some other format, like PNG. This should get rid of that metadata blob. After that you can convert your image back to JPG and resize it any way you wish. From that point on you will be able to reduce file size below 12 MB.

There are probably dedicated tools that can simplify the process of stripping that metadata from the files.