Beyond Preview's Export — Compress a Whole Folder at Once
Preview's File → Export handles one image at a time. TinyPixels batch-compresses entire folders on Mac, with more formats and finer quality control.
How to batch compress instead of using Preview's Export
Download and open TinyPixels
Free to install on Mac — no extra software needed beyond this.
Drop the whole photo folder in
No more opening and exporting each file one at a time.
Set your quality and format
Convert to WebP or AVIF, or just compress in the original format.
Compress and collect the output
Every image processes with consistent settings in one pass.
Where Preview's export falls short
macOS Preview is a genuinely convenient way to quickly resize and re-export a single image — no extra app needed, built into every Mac. For one file, it's often the fastest option available.
The limitation shows up as soon as you have more than one or two images: Export has no batch mode, so compressing a folder means opening each file, exporting, and repeating — every single time. There's also no format conversion to WebP or AVIF, and the quality slider is basic compared to dedicated compression tools.
TinyPixels covers the exact same use case — compress an image for smaller file size — but scales to any number of files. Drop a folder once, and every image compresses with consistent settings.
Batch instead of one-by-one
Compress an entire folder in one action instead of repeating Export per file.
More format options
Convert to WebP or AVIF, not just re-save as JPEG or PNG.
Finer quality control
A precise quality setting tuned for real compression libraries, not a basic slider.
Folder watch automation
Set a folder to auto-compress new files without opening the app.
The Automator/Shortcuts workaround, and its limits
macOS power users sometimes build an Automator workflow or Shortcuts automation that chains Preview's export action across a folder of files — a reasonable workaround that avoids manually repeating the Export dialog. It works, but it's a workflow you have to build and maintain yourself, and it's still bounded by whatever compression Preview's export actually applies under the hood (a basic quality slider, no lossless PNG optimization, no AVIF).
A dedicated batch compressor gets you the same "process a whole folder" outcome without building the automation yourself, plus better compression results and more output format options than Preview's export ever exposes.
Common mistakes with Preview-based compression
Assuming Preview's quality slider behaves like a real compressor's
It's a simpler control than dedicated tools' quality settings — don't expect the same fine-grained size/quality tradeoff.
Exporting screenshots as JPEG through Preview
Preview's JPEG export applies lossy compression poorly suited to flat-color UI screenshots — PNG or WebP typically compress screenshots far better.
Building an Automator workflow for a one-time task
If this is a recurring need, the investment in automation pays off; for a single batch, a dedicated app with folder support gets you there faster.
Not checking output file sizes before sending a large batch
Whatever tool you use, spot-check a few compressed files before committing to a full folder run, especially the first time you try a new quality setting.
Migration notes: what changes, what doesn't
| What | Preview | TinyPixels |
|---|---|---|
| Where you export | File → Export, per image | Drag a file or folder into the app window |
| Batch support | None — one image at a time | Unlimited folder batches on Pro |
| Format options | Re-save in the same or a few basic formats | PNG, JPEG, WebP, AVIF, GIF conversion |
| Quality control | Basic slider, no lossless PNG optimization | Dedicated lossless and lossy modes with fine control |
For a single quick export, Preview remains the fastest option since it's already installed. The switch pays off once you're handling more than a handful of files or need a format Preview's export doesn't offer.
Frequently asked questions
Can Preview compress multiple images at once on Mac?
No. Preview's File → Export function handles one image at a time — resizing and re-exporting a folder of images means repeating the same manual steps for every file.
Does Preview have a precise quality slider for compression?
Preview's export quality slider is basic compared to dedicated compression tools, and it doesn't support format conversion to WebP or AVIF, or lossless PNG optimization.
Is there a Mac app that batch-compresses images like Preview exports one file?
Yes. TinyPixels applies the same drag-and-export simplicity but to an entire folder at once, with more format options and finer quality control than Preview's built-in export.
When is Preview's export good enough?
For a single one-off image, Preview's Export is quick and requires no extra software. For more than a handful of files, or when you need format conversion beyond JPEG, a dedicated batch tool saves significant repeated manual work.
Can Automator or Shortcuts fill the batch gap in Preview?
To some extent — macOS Automator and the Shortcuts app can chain "Export" actions across multiple files, effectively scripting around Preview's one-at-a-time limitation. This requires building and maintaining a workflow, though, versus a dedicated app where batch processing and format conversion are the default behavior.
Does Preview support lossless PNG optimization?
Preview's export re-encodes images using standard system codecs, without the more aggressive lossless optimization techniques (like palette reduction or filter optimization) that dedicated PNG-focused tools use. For PNGs with large flat-color areas — screenshots, UI mockups — a specialized compressor typically produces meaningfully smaller output.
Compress your whole photo library at once
Free to start. No credit card, no account, no cloud. See Pro pricing →
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