I am looking to do some custom logos and headers for a newsletter and the fire department I belong to.
There are two main types of graphics package.
* Image/photo editors are mainly about manipulating photos and scanned images composed of pixels. Examples: Photoshop, Pixelmator, Affinity Photo, the GIMP...
* Vector illustration packages are mainly about building images up from geometric shapes, curves, text etc. that can be freely edited, enlarged, reduced. Examples: Illustrator, Affinity Designer, Inkscape, iDraw, EazyDraw...
There is a
huge overlap between the functionality of these two types - most photo editors include vector tools and most vector packages can manipulate photos, and if you're really familiar with one package you might find it practical to use it for everything, but its usually best to have the right type for the job.
For logos/banners etc. I'd say you want a vector package.
Inkscape is the free option and technically very powerful but let down by the usual open-source, clunky, cross-platform user interface. Affinity Designer is a fairly new, and much slicker looking paid-for option designed for Mac, and would be good for logos. EazyDraw isn't as shiny, but has nice features for plans, diagrams, graphs (probably not relevant to you). iDraw, I haven't used (but has good reviews).
My real recommendation is Xara Designer, but since that's Windows only, not very helpful
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I've been running it under Parallels. However, I think I'll switch to Affinity Designer just as soon as they've added proper arrowheads - which has been promised. Dashed lines appeared a week or so back. That wouldn't be a dealbreaker for designing logos.