While you should generally follow the alt text formula, your final answers may look a bit different than those listed here.
Example 1: {palmerpenguins}
ggplot
Alt text: A histogram of penguin body masses where Gentoo penguins have body masses that are about 37% larger than Adelie and Chinstrap penguins.
Example 2 (from The New York Times):
Alt text: A dot plot of monthly global temperatures compared to the 20th-century average, where monthly global temperatures are increasing over time. Nearly every month since the mid-1970s is warmer than the 20th-century average, with 12 record-breaking hot months occurring between 2015-2023.
Example 3 (Fig 1A from Chapman et al. 2024):
Alt text: A heatmap of global species observations where the highest concentration of observations occur in high-income countries, particularly in the USA and European nations.