docs: compress screenshots

README.md

@@ -6,7 +6,7 @@ Inspired by projects like [teddit](https://codeberg.org/teddit/teddit), [nitter]
 
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-| <img src="./public/img/misc/preview.png" title="screenshot (desktop screen, light mode)" width="1500" /> | <img src="./public/img/misc/preview2.png" title="screenshot (mobile screen, dark mode)" width="385" /> |
+| <img src="./public/img/misc/preview.jpg" title="screenshot (desktop screen, light mode)" width="1500" /> | <img src="./public/img/misc/preview2.jpg" title="screenshot (mobile screen, dark mode)" width="400" /> |
 
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