OPML to JFIF Converter

OPML (Outline Processor Markup) is XML for hierarchies: nested <outline> elements, each with text and optional attributes. It is the silent standard behind podcast and RSS subscription lists — every "export subscriptions" button produces one — and the interchange format for outliners like Workflowy, Dynalist and OmniOutliner.

An outline is already half a document: Pandoc turns OPML hierarchies into Markdown headings, Word outlines or HTML pages with the nesting preserved, and can write OPML back out so a bulleted plan becomes an importable tree in your outliner of choice.

JPG (short for JPEG, the Joint Photographic Experts Group committee that standardized it in 1992) has been the default photo format for over three decades. It compresses photographs using the discrete cosine transform: the image is split into 8×8 blocks, and details the human eye is bad at noticing are discarded. The result is files many times smaller than uncompressed data, at a quality level you control when saving.

In practice JPG is unbeatable for photographs and smooth gradients — camera memory cards, messaging apps and the web all assume it. It is a poor fit for screenshots, logos or anything with sharp edges and flat color, where compression leaves visible ringing around text. There is no transparency support, color depth is capped at 8 bits per channel, and every re-save with compression compounds tiny generational losses.