Need help changing the color on an image

ETA: There you go!

I use GIMP. It takes some time to get used to it (compared to something like paint), but it can do a lot of neat stuff (and it's free). Paint.net is also free and useful, and according to most of what I've read (no personal experience) it's more intuitive. Both should have plenty of online tutorials (and plenty of questions answered above in the "Teach a Man to Fish" thread).


Now for the actual "what I did" in GIMP to change the color:

I added an alpha channel (transparency) and used the "select by color" tool to pick the white background. I erased all of that (only the black was left). From there, you can mass-adjust the entire image (note: transparency means the image doesn't have anything there...if we left the white background, we'd get a blue hue on it.) to give it (essentially) any color you want using Hue, Saturation, and Lightness sliders. I then selected the entire transparent part and replaced it with a white background (which isn't really necessary. .jpg doesn't handle transparency, so it would have automatically given it a white background. Other formats (.png, .gif,...) can have transparency (and if you want, I'd be happy to make the background transparent for you).


The image wasn't perfectly monochrome (black and white...NO shades of grey (hard to see, but they are little flecks in there), but if it was, you could use the "select by color tool" to pick the black (image) part and "replace" with any color from a grid.


You should download GIMP and try it (or paint.net, but my instructions won't be as accurate), or something else in the Teach a Man to Fish thread!

And if you do, but I wasn't clear enough here on how to do it, let me know. I'll see if I can explain it better.

Doc,
Great description.

Now, as a resident Paint.net enthusiast, here how I would do it using my software suite:

1. Open Image in Paint.net
2. Add a blank layer on top of your train
3. Use the paint bucket to fill the entire layer. Be sure to use your desired blue. I don't know what the color description. You can enter colors in RGB scheme though if you want to match an exact hue.
4. Change the blue layer's property to "additive."
5. Save image as PNG or JPEG. This will merge your layers and your image is complete.

Thanks for the help, guys. Now if I wanted to change the background color?

I downloaded paint.net and got it.

Why didn't you guys tell me about this a long time ago? Screw MS Paint.