While there are many different types of plotters like drum plotter, cutting plotter etc, An inkjet plotter is basically a large format printer that specializes in printing graphs, schematics, architecture and construction drawings etc.
These are cheaper than wide format photo printers since they usually have fewer number of ink cartridges and they generally do not have the same quality of prints.
In the list above, the HP Designjet T100 and the Epson SureColor T5170 are plotters since they only have a 4 ink system and therefore have a lower operating cost but also less color fidelity as compared to the rest.
While they specialize for engineering, construction and architectural firms, it does not mean that you cannot use them for printing photos, posters etc.
You most certainly can, but the quality will be not be as great as the dedicated large format photo printers like the Canon imagePROGRAF PRO-2000.