A country flag image could be used for any number of reasons; perhaps the most popular method would be on a website which allows the user to either select the language of their choice or to access the site-version dedicated to their country.
The problem is that there are many, many sites where you can download and use the national flag image of your choice, but the most of these are pretty bland and basic and don’t really offer the graphical expectations of modern web design. We need better.
What we have for you today is a small (as in the number of sets), yet extensive (as in the number of actual flag icons), collection of professionally designed country flag icons and banners that you can use for free in your own projects.
Adventure Pennants & Vintage Flags (Envato Elements, AI, EPS, PSD & SVG)
2600 Flat & Shiny Flag Icon Set (Free, PNG)
64 Simple Flags Icons (Free, PSD)
260 Rounded, Square & Rectangular Country Flag Icons (Free, SVG, EPS, PSD & PNG)
30 Country Flag Icons (Envato Elements, AI, PNG, PSD & SVG)
58 Country Flag Icons (Free, PSD)
114 Vector Flags Icons (Free, SVG & PNG)
Open-Source Flag Icon Set (Free, PNG & Sketch)
244 Flat World Flag Icon Set (Free, PNG)
Flags Icon Pack (Free, PNG)
famfamfam Mini Flag Icon Set (Free, GIF & PNG)
Free Country Flags in SVG Format (and CSS for Integration)