Tutorial: View Large Images on iOS and Android

Abstract. Long infographics and wide charts get scaled down until they are unreadable on phone screens.

An infographic designed for a desktop is 1080 pixels or wider, and often very tall.

When a social network or browser scales the whole image to fit the width, the text shrinks to the point of illegibility – the “small text in a big chart” problem.

This tutorial covers four ways to read them:

• pinch-zoom in the built-in photo viewers
• zooming inside the Facebook app
• saving the image to the camera roll for full-resolution zoom
• converting the image to a paged PDF

A phone screen is about 400 points wide.

Prerequisites

• A phone: iPhone (iOS 15 or newer) or Android (any recent version).
• The image you want to read, either as a file or as a link.
• Optional: a Mac or PC for the PDF conversion

Step 1: Pinch-Zoom in the Built-In Viewer

Open the image in the phone’s photo app and pinch to zoom.

On iPhone:

1. Save the image: in Safari, long-press the image and choose Save Image. In most apps, tap the share button and choose Save Image.
2. Open the Photos app and find the image.¹
3. Pinch outward with two fingers to zoom in. iOS Photos zooms to the image’s native pixel resolution, so a 1920x1080 capture stays sharp.
4. Drag with one finger to pan across the image.

On Android:

1. Save the image: in Chrome, long-press and choose Download image (or Save image). Open the Files or Gallery app.
2. Open the image in Google Photos or the Gallery app.²
3. Pinch to zoom and pan the same way.

This works for moderately large images. The limit: once you zoom in, you see only a slice, and you must pan repeatedly to read the whole thing. For a tall infographic with many sections, paging (Step 4).

Step 2: Zoom and Save Inside the Facebook App

Facebook displays photos in its own in-app viewer. On both platforms, tap a photo in the feed to open it full-screen, then:³

1. Pinch outward with two fingers to zoom in; pinch inward to zoom out.
2. Drag with one finger to pan across a zoomed image.
3. Double-tap to zoom in, double-tap again to zoom back out.

On iPhone, you can also hold the photo in the feed and choose Save Photo (or tap the three-dot menu in the viewer) to save the image to the camera roll, then zoom in the Photos app exactly as in Step 1.

On Android, long-press the photo in the feed and choose Save image (or tap the three-dot menu in the viewer) to save it, then open it in Google Photos or the Gallery app and zoom as in Step 1.

The catch: the in-app viewer only zooms as far as the version Facebook serves. Facebook re-encodes uploads, so a very tall image may still look soft at maximum zoom. When that happens, save the photo as above and zoom the saved file – the saved copy is the highest resolution Facebook has. If the saved copy is still soft, the uploader’s original was larger than what Facebook serves; use Step 3 to look for a full-resolution original elsewhere, or ask the poster for the original file.

Step 3: Open the Full-Resolution Original

The most common reason a chart is unreadable is that the phone is showing a compressed preview, not the original file. Open the original:

• If the image is on a web page, long-press and choose Open image in new tab, then pinch-zoom the tab. This bypasses the page layout and gives you the raw image.
• If the image was emailed or messaged, save the attachment first, then open it from the camera roll. Messaging apps often downscale previews; the saved attachment is usually the full file.
• On Android, Chrome’s “Request desktop site” can force a page to serve the full-size image instead of a mobile thumbnail.

Check the file’s pixel dimensions if you can: an image below about 1000 pixels wide will never be sharp when zoomed on a phone, no matter the method.

Step 4: Convert the Image to a Paged PDF

A PDF turns a tall image into pages you can swipe instead of pan. This is the best method for a very long infographic – a chart with footnotes, a long screenshot, a book page.

On a Mac (or any computer):

1. Open the image in Preview.
2. Choose File > Print, then in the print dialog set the paper size and orientation so the pages roughly match the image’s proportions.
3. Click the PDF button (bottom-left) and choose Save as PDF.
4. Transfer the PDF to the phone (AirDrop, Files, email, or a cloud drive).

On the phone:

• iPhone: open the PDF in the Books app or Files app.⁴ Swipe between pages; pinch to zoom any page.
• Android: open the PDF in Google PDF Viewer, Drive, or any PDF app. Swipe between pages, pinch to zoom.

The PDF method also works for web pages: on iOS, use Safari’s share sheet > Print > pinch outward on the page preview > Save as PDF. This captures the whole page, not just the visible screen.

Related: Create Phone-Friendly Cards

To make your own graphics readable on phones, see the companion tutorial, “Generate Mobile-Friendly Charts” (2026-08-14-tutorial-generate-mobile-friendly-charts), which covers splitting a tall infographic into 1080x1350 carousel cards, sizing fonts for the display width, rendering with a headless browser, and pixel-level verification.

Verification

1. Pick one of the methods above and open a large image.
2. On the phone, zoom to 100% (or the maximum) and confirm the text is sharp, not pixelated.
3. If the image is a multi-section chart, confirm you can read each section without zooming back out and re-finding your place.
4. In the Facebook app, open a photo and confirm pinch-zoom works; if the image is soft at maximum zoom, save it and zoom the saved copy.
5. For the PDF method, confirm the pages are paged (not one continuous strip) and that swiping between pages works in the phone’s PDF reader.

Notes