Genealogica Grafica is an application which generates various family tree charts and reports from GEDCOM files, saving them as HTML so they're ready to share online.
The program interface is sometimes confusing and unintuitive. You might expect an "Import" or "Open" GEDCOM option, for instance, but no - "Restart with GEDCOM" is the one you need, bizarrely. (And don't click "Produce and view HTML" until you've done that, or the program crashes.)
GEDCOM handling is better, fortunately, with Genealogica Grafica highlighting inconsistencies in a report.
Choose a starting person and it's easy enough to produce an ancestor or descendant chart, circle or tree, intermarriage, pedigree loss or relationship charts.
These aren't static images, either. Create an ancestor chart and you'll get both the tree and a text report of all the individuals it contains, and their details, as extracted from the GEDCOM. These are linked - clicking a name in the chart jumps to that person in the tree - and they're HTML-based and ready to share immediately on your own website.
Please note, this is shareware, and one or two functions (including printing) are disabled until you make a donation of some (any) kind.