The size restriction is much higher than 150K and has been for awhile now.

I use Adobe Photoshop to re-size my scans.
I do it for faster loading so people with slower computers don't get bored waiting for it to upload.
Plus, on your monitor, you won't be able to tell much of a difference.
See if you can notice a difference between 1200X1200 pixels.

Here's a page that's 918K, 1200X1200 pixels without re-sizing:

Here's the same page re-sized to 231K, 1200X1200 pixels:

How about the difference between these 800X800 pixels?

The same page at 436K, 800X800 pixels:

At 99K, 800X800 pixels:

In Photoshop I use Save for Web... option.

I Import my Epson in Photoshop.

What program are you using to scan?