One way would be to:
- use Inkscape,
- resize the canvas to be whatever size you want your images to be,
- create a text layer and type in the code for the icon you want,
- open text options (select the text layer, then go to Text > Text and Font in the top menu),
- select the text in the layer,
- select the Dicier font in the fonts list,
- click 'Apply' under the fonts list,
- if you want, change the icon (e.g. rescale, recolour), and
- export as a .png file (using File > Export PNG Image... in the top menu.
In order to access all versions of Dicier in Inkscape you'll need to install the 'LibreOffice' font files, because the two apps handle fonts the same way.
If you're using the advanced features (like the stylistic sets or character variants) then you'll also need to go to the 'Features' tab of the 'Text and Font' area in Inkscape. This may take a little while to load (maybe 10s) due to the number of OpenType features in Dicier. In that tab you'll find most of the advanced features under 'Feature Settings', plus discretionary ligatures under 'Ligatures' and slashed zero under 'Numeric'.