What are some alternatives?
When comparing ImageOptim and Transmit, you can also consider the following products
CodeKit - CodeKit allows you to optimize the performance of your website by automatically and efficiently compiling a variety of popular languages.
Cyberduck - A libre FTP, SFTP, WebDAV, S3, Backblaze B2, Azure & OpenStack Swift browser.
TotalTerminal - TotalTerminal is a plugin for Terminal. app which provides Quake-style terminal window available on keyboard shortcut.
FileZilla - FileZilla is an FTP, or file transfer protocol, client. It lets individuals transfer single files or batches to a web server. For many years, FTP was the standard for website design. Read more about FileZilla.
TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!
Forklift - The most advanced dual pane file manager and file transfer client for macOS.