Gmail caps attachments at 25 MB, a limit you hit fast once you're talking high-resolution photos, video, or working files (PSD, Premiere, InDesign). Past that, Gmail either refuses to send outright or automatically switches to a Google Drive link.
The automatic Google Drive workaround
If your file goes over the limit, Gmail offers to drop it into Google Drive and send a link instead. It works, but it wasn't built for client delivery: a generic link, no control over how it looks, no way to see who downloaded what.
Compressing it, within limits
Zipping a folder sometimes shrinks the size, especially for text or lightly compressed files, but makes little difference on JPEGs or videos already compressed on export. Don't count on a ZIP to squeeze a file that's twice too heavy.
For client delivery, switch tools entirely
Beyond a one-off fix, if you're regularly sending heavy files to clients, that deserves a dedicated tool rather than a Gmail workaround every single time. xFer handles large volumes with no artificial 25 MB-style cap, and delivers on a page in your brand instead of a generic Drive link.
The real gain isn't just technical: your client gets a polished delivery experience, not a last-minute patch job.
In short
Gmail workarounds (auto Drive, ZIP) work fine for a one-off send. For regular client delivery, a tool built for large files removes the cap and improves the image you send with every delivery.