Everything happens in one window, and the image you export is exactly the image you see. Once your theme and size are set they persist between launches, so only the first snippet takes any thought — every one after that is paste and export.
1. Paste your code
Copy a snippet and paste it straight into Codeshot with ⌘⇧V. That shortcut replaces the whole source from anywhere in the window, so you do not have to click into the editor first.
Highlighting is applied as you paste. The language is detected from the code itself, across 60 languages, and you can override it from the Language menu when a short fragment is ambiguous — three lines of C and three lines of C++ look identical to any detector.
Pasting the text rather than screenshotting your editor is the important part. It leaves behind the cursor, the selection highlight, the gutter icons, and your editor's line width, none of which belong in the image.
2. Pick a theme
There are 30 syntax themes, each with a light and a dark variant. You can see all of them side by side rendered with the app's own stylesheets.
Two things worth knowing when choosing. Match the theme to your editor if you want the image to feel familiar to your audience — Xcode for Swift, GitHub for almost anything. But if the image is going somewhere it will be viewed small, contrast matters more than familiarity, and the softer light themes lose their structure when scaled into a feed.
3. Choose a backdrop
The snippet sits on a canvas, and that canvas can be one of 19 macOS wallpapers, one of 92 gradients, a solid colour of your own, or an image you supply.
You can also turn the background off entirely and export with transparency, which is what you want when the image is going onto a slide or a page that already has its own background.
4. Fine-tune the frame
Set the window corner radius, the padding inside the window, the margin around it, and the drop shadow. Traffic lights and the window title can be switched on or off, and you can use any monospace font installed on your Mac.
These are the settings you touch once. Get them how you like them and they carry across every future snippet, which is most of why the tenth image takes a few seconds rather than a few minutes.
5. Export at the right size
Let the size follow your content, or lock it to a ratio: 1:1, 4:3, 3:2, 16:9, 9:16, 2:3, or 3:4. The presets are shortcuts over plain width and height fields, so any other ratio is a matter of typing it.
Export at 1×, 2×, or 3×. Use 2× as a default — a 1× export of small text looks soft on a retina display, and it is the single most common thing that makes a code image look amateur.
Then take it out of the app whichever way suits: copy straight to the clipboard with ⌘⇧C, drag the preview into another app, or save with ⌘S.
Where it is going
The right ratio depends entirely on the destination, and it is worth getting right because every platform crops differently. There are per-platform guides for X, LinkedIn, and Facebook, and size guides for the rest.
One last thing, said plainly: an image cannot be copied, searched, or read by a screen reader. When the code is meant to be used rather than looked at, post a link to the source alongside the picture.