G.E. Database Merchant Suggester (Need advise)

This is a bit complicated so I' am just going to go though this step-by-step.
I' am using Visual Basic 2008 Express.
(This is all speculation and brainstorm, I'll be working on the project as soon as I post this).
1:The general idea of the program is to open the items chart from the database (by chart I mean this: )
in a small browser (size, 456, 351, as their all the same size)
2.Then check the chart for certain merchanting properties. Such as, when both lines are going down and intersect, the price of the item will rise and its at this time its best to buy. This is what I want the program to look for.
3. Have the program cycle through either a select number of items (or items with certain values in their name, such as dragon, rune, etc) or (if you have the time) have it cycle through the entire database.
4. The program can search for items of a particular price range defined by the user and search the whole database or, as said before, a select range of items.

Easy enough to type out, hell to code.
I can do everything by myself, besides number 3.
I want the program to look for intersecting lines or lines that are close to crossing, but they need to be going down. If you study the items chart the newest points are running off the page, this makes it a bit easier for me (so I dont have to deal with the intersections previously made on the chart if I focus on a certain range) but I am curious as to how I'd pull this off.
The background of each chart is different then the next, the lines there are randomized so any suggestions leading there would be pointless.
I was thinking I can identify the lines by their color, yellow and blue. Set a specific range, such as 20 pixels from the right side of the image (as this is the only part I'll need -I think-. (If I didnt explain anything thoroughly enough please ask and I'll answer to the best of my ability).

I am a bit of a novice, I can program small programs without the use of references but this has me stumped. So hopefully someone can help me answer these questions.
How do I identify if the yellow line is going up or down?
How do I identify if the blue line is going up or down?
How do I identify the space between the two end points?
How do I specify the end point that runs off the graph? (As the line has a consistent color and I cant define a specific spot as the prices change constantly).

I am getting to work on it now, if anybody has any tips or would like to help me out you can post here or IM me at [email protected]

 

Well, there's already something like this out.
I think its really good for G.E. merchanting.

http://merchstation.thegrandexchange.com/

 

If you need help with getting all the items and ids on the GE, I parsed them out a few days ago, and have a full, updated list of every GE tradeable item.

~Sandstorm

 

Thanks for the link. I found I can cycle through the images just by playing with the url for every graph, its turning out easier then I'd thought it'd be.