Writing papers and making figures is and always will be a big part of what scientists do. Many of us use open source software, such as Fiji, to process images however the figure is often finalised in commercial software - typically from Adobe. Needless to say neither Photoshop nor Illustrator are designed to make scientific figures.
Two groups have recently introduced plugins that leverage the tools available in ImageJ/Fiji to make scientific figures. Both tools are made by scientists introducing innovative concepts specifically designed to make scientific figure making easier and more controlled.
FigureJ from Jerome Mutterer and ScientiFig from Benoit Aigouy are well documented, open source (FigureJ ScientiFig) and published:
Each tool is available in Fiji through its own Update Site.
Finally the OMERO team is also rolling out a Figure making plugin showcased here http://www.youtube.com/watch?v=anJPPx7uoUM.
Making figures will never be the same.