Copy the snippet for the size you want. The images are hosted at zerosay.com, so they stay up to date; or download the files from this kit and host them yourself. The link carries ?ref=partner so we can see the traffic came from a partner site.
<!-- zerosay-1200x628-dark.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-1200x628-dark.png" width="1200" height="628" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-1200x628-light.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-1200x628-light.png" width="1200" height="628" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-160x600-dark.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-160x600-dark.png" width="160" height="600" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-160x600-light.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-160x600-light.png" width="160" height="600" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-300x250-dark.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-300x250-dark.png" width="300" height="250" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-300x250-light.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-300x250-light.png" width="300" height="250" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-300x600-dark.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-300x600-dark.png" width="300" height="600" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-300x600-light.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-300x600-light.png" width="300" height="600" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-336x280-dark.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-336x280-dark.png" width="336" height="280" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-336x280-light.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-336x280-light.png" width="336" height="280" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-468x60-dark.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-468x60-dark.png" width="468" height="60" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-468x60-light.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-468x60-light.png" width="468" height="60" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-728x90-dark.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-728x90-dark.png" width="728" height="90" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-728x90-light.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-728x90-light.png" width="728" height="90" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-970x250-dark.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-970x250-dark.png" width="970" height="250" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>
<!-- zerosay-970x250-light.png --> <a href="https://zerosay.com/?ref=partner" target="_blank" rel="noopener"> <img src="https://zerosay.com/brand/kit/banners/zerosay-970x250-light.png" width="970" height="250" alt="Zero Say — zero-knowledge private messaging" loading="lazy" style="border:0"></a>