[Vrul]

I think you can use the id number in place of an actual path based on Blizzard's code:

function CreateTextureMarkup(file, fileWidth, fileHeight, width, height, left, right, top, bottom, xOffset, yOffset)
    return ("|T%s:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d|t"):format(
          file
        , height
        , width
        , xOffset or 0
        , yOffset or 0
        , fileWidth
        , fileHeight
        , left * fileWidth
        , right * fileWidth
        , top * fileHeight
        , bottom * fileHeight
    );
end
 
function GetCurrencyString(currencyID, overrideAmount, colorCode, abbreviate)
    colorCode = colorCode or HIGHLIGHT_FONT_COLOR_CODE;
 
    local currencyInfo = C_CurrencyInfo.GetCurrencyInfo(currencyID);
    if currencyInfo then
        local currencyTexture = currencyInfo.iconFileID;
        local markup = CreateTextureMarkup(currencyTexture, 64, 64, 16, 16, 0, 1, 0, 1);
        local amountString;
        if abbreviate then
            amountString = AbbreviateNumbers(overrideAmount or currencyInfo.quantity);
        else
            amountString = BreakUpLargeNumbers(overrideAmount or currencyInfo.quantity);
        end
        return ("%s%s %s|r"):format(colorCode, amountString, markup);
    end
 
    return "";
end