Download and install the latest version of Filestar.
Right click on one or more Jtf file(s) on your desktop and select Convert with Filestar.
Type convert to heif in the search box.
Press Convert.
Or let an AI agent do it: filestarcli -i file.jtf -c "convert to heif" (how).
Documents - File Explorer─☐✕
This PC › Documents
Home
Desktop
Downloads
Documents
Pictures
Music
.jtfContract.jtf
.xlsxBudget.xlsx
.pdfReport.pdf
.pngLogo.png
Filestar*Help✕
Drop files here to get started
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Let your AI agent convert JTF to HEIF
Claude Code, Codex, Cursor and other agents can do this on your computer with Filestar. Your files stay on your machine.
Install Filestar and add it to your agents:
npm install -g filestar
filestarcli agent install
Then ask your agent:
“Convert the JTF files in my Downloads folder to HEIF”
Or run it yourself:
filestarcli -i file.jtf -c "convert to heif"
Runs on your computer, so your files stay on it. Works on Windows, macOS and Linux. 50 free conversions with the npm install, no account needed.
Can my AI agent convert JTF to HEIF?
Yes. Install the Filestar CLI with npm install -g filestar and your agent can run filestarcli -i file.jtf -c "convert to heif" on your computer, so your files stay on it.
The JTF file format, associated with Hayes JT Fax, represents a type of image file specifically designed for fax documents. It is used to store scanned or digitally created documents that are meant to be sent or received through a fax service. The format is optimized for the efficient encoding of black and white images, typical of fax transmissions, ensuring that text and simple graphics are clear and legible. JTF files support a form of compression to reduce file size without significantly compromising the quality of the document, making it suitable for quick transmission over phone lines.
Based on HEVC (High-Efficiency Video Coding), the HEIF format is an image file container with one or multiple images and is the default image format for Apple Live Photos. It replaced the JPEG format as it's smaller in size and has lossless compression ensuring high-quality photos.
