i use irfanview 4.00 for my resizing... how do you limit the compression?
Setting compression in Irfanview is done like this:

After you've set your quality you need to check the image for its size. If it is either bigger or smaller then you need to adjust the slider and resave that image again. You need to check it for size again and go over this process again untill you have an image that is 150kb or less.
Irfan view is nice but I find it to much hassle to get an image that weights around 150kb. I like Photoshop and Paintshop Pro a lot better.
I would advise you to get a copy of either one, though the latter might be a cheaper choice. Also ... take a look at
this.