Inkscape is a pretty fancy tool. It runs on Linux (as well as Windows and such). It is all about vector graphics, which at this point is neither here nor there to me, as long as it allows me to draw with my mouse.
It is already installed on my Fedora linux system and is available as a regular package. I just type at the command line:
inkscape hubbard.jpg
You want to use "File -- Export". When you do this, the entire right side of the GUI turns into an export dialog. At the very bottom is an EXPORT button you can use when you get all the settings the way you like them. By default it will export as PNG, so you should take care to select JPEG before clicking the EXPORT button. I noticed that the PNG file it saves is about 10 times bigger than the JPEG file.
To select color, I just clicked on the rainbow of options across the bottom of my screen. You do this immediately after drawing something, and the selection will "stick" until you change it after some other object.
To tell Inkscape what I want the mouse to do, I click on a selection from the column on the left. Among many other things, I can create circles, rectangles, and freehand lines.
Boxes and circles are easy, but the freehand drawing tool gives me a fight. It wants to "fill", which is the last thing I want. To set the stroke width, you use Object -- Fill and Stoke", select Stroke style and then adjust the width -- after you draw a path. For whatever reason, the width setting does not stick. And when I select a color at the bottom, it fills with that color, but does not change the path color. This freehand drawing tool seems like the orphan child of Inkscape. Not intuitive, and one tutorial has already cautioned me to avoid it.
To get rid of this fill thing, you get the Fill and Stroke menu, select the "Fill" tab and then select the "x" to say "no paint" (you think this will close a window, but it is actually an entry in the menu). None of this works. I get a black line no matter what color I select, and it does not remember my stroke width.
Reading some more, I learn that Inkscape has limitations drawing on top of a raster object like a JPEG file. This all may work differently if I work on a blank canvas.
The Calligraphy drawing tool seems to be better on top of a JPG, but you need to change to a marker instead of a dip pen and reduce the width. Larger widths give you a two line train track effect. Also to change color, you must use the color spectrum at the bottom of Inkscape, ignore the color wheel thing inside of Fill and Stroke.
Tom's Digital Photography Info / [email protected]