Jennifer Love Hewitt -- Sues 'Shark Tank' Wannabe ... You Bit My Image

Jennifer Love Hewitt's face is getting spread all over the Internet and she ain't happy about it -- she is suing the company using her image to promote a product the "Shark Tank" investors called a total "scam."

The product is called Slim Spray ... which claims to be an oral vitamin spray that will boost your energy and shed pounds. According to the lawsuit ... J.Love's face and bod have been attached to spam ads (you might have one in your inbox right now) that make it look like she endorses the stuff.

Jennifer claims she's worked too hard to develop her "stellar reputation and credibility" to have it all blown by Slim Spray -- and says she never authorized the company to use her image.

As for the photo of her holding the product -- she implies someone put it in her hand on a red carpet event, snapped a pic ... which ended up on Slim Spray's website and ads.

In the docs -- filed Wednesday in L.A. -- she points out the "Shark Tank" crew dismissed the spray as nothing more than a "hustle."