Hi Elmo101, I dont do illustrations and I dont know which software are you using, but, multiplying the width by the height in pixels have to be more than 3 million, for example, an image 2000 pixels wide x 1500 pixels high would have exactly 3 megapixels,
You are probably increasing the print size of the image, but decreasing its resolution (like increasing from A4 150 pixels/inch to A3 but 72 pixels/inch) so it end up with the same amount of pixels or something like that.
Make sure you look for the size of the image in pixels not the print size and you wont miss it.
I hope this explanation works for you.
Canon EF 70-300mm IS/USM f/4-5.6
Canon 100mm f/2.8 USM/Macro