For a quick and dirty colorization of images, hue adjustment is your best friend. However, the danger with using hue adjustment is that you don't have much control over your tones compared to when you were using color curves.
To add the hue adjustment node in Blender's Node Editor Window, press SHIFT A then choose Color then finally Hue Saturation Value. This will add the Hue Saturation Value Node which is basically used to adjust the image's tint, saturation (grayscale, vibrant colors), and value (brightness). Later on in this article, you'll see just how useful this node will be. But for now, let's stick with just the hue adjustment aspect of this node.
Move the mouse over the image to enlarge it.
(Adding the Hue Saturation Value Node)
(Hue Saturation Value Node)
To colorize your images, simply slide the Hue slider. When using the hue slider, it's a good rule of thumb to keep the adjustments at a minimum, but for other special purpose, you can set them the way you want to. Below are some examples of different values of the Hue Adjustment.
(Hue at 0.0)
(Hue at 0.209)
(Hue at 0.333)
(Hue at 0.431)
(Hue at 0.671)
(Hue at 0.853)
(Hue at 1.0)