ARC: Aspect Ratio & Resize

Help

Get the size you need without fighting the math.

Start with the original dimensions, choose the new size, check the preview, then copy or export the finished image.

Showing all help topics.

01

Getting Started

ARC: Aspect Ratio & Resize works from left to right: Original Size, New Size, Preview, then Copy or Export.

  • Original Size is the starting width and height. With an image loaded, those fields use the image's real pixel dimensions.
  • New Size is the output size being calculated, copied, or exported.
  • Lock Proportion keeps the same shape while the app solves the missing width or height.
  • Use value chips for quick copies, or choose an output template and click Copy Output.

Example: A 1536 x 1024 image needs to be 1200 px wide. Type 1200 in New Size W; with Lock Proportion on, the app solves H as 800.

02

Resize Image

Resize Image changes the image file itself to the New Size dimensions.

  • Use it when the image should scale directly and keep the same shape.
  • If the New Size ratio is different, the app warns before producing a stretched image.
  • Keep Lock Proportion on for proportional resizing.
  • Switch to Resize to Frame when you need an exact outside size without distortion.

Example: A 2400 x 1600 photo needs to become 1200 x 800. Use Resize Image, enter 1200 for New Size W, and export.

03

Resize to Frame

Resize to Frame creates a final output with the exact outside dimensions shown in New Size while preserving the image's ratio.

  • Fit Inside keeps the whole image visible and may add padding.
  • Fill & Crop fills the frame edge to edge and crops only what does not fit.
  • Keep Scale keeps the final output size fixed while you choose how much source image lands in that frame.
  • Use Frame Placement when the inline preview is too small for precise composition.

Example: A 1600 x 900 image needs a 1200 x 628 ad slot. Resize to Frame keeps the final output exact without stretching the source.

04

Fit Inside

Fit Inside keeps the entire image visible inside the New Size frame.

  • Use it when nothing can be cropped: product images, documentation captures, screenshots, and portfolio samples.
  • If the frame and image have different shapes, the app adds padding instead of cropping or stretching.
  • PNG and TIFF can preserve transparent padding. JPEG/JPG, HEIC, and HEIF use an opaque background.
  • Switch to Fill & Crop when the frame must be filled edge to edge.

Troubleshooting: Empty bars mean Fit Inside is preserving the full image. That is expected when the image and frame ratios differ.

05

Fill & Crop

Fill & Crop fills the entire New Size frame while preserving the image's ratio.

  • Use it for hero images, thumbnails, cards, banners, social posts, marketplace covers, and previews where padding would look wrong.
  • The output has no padding, but content outside the visible frame is cropped.
  • Drag the visible area, use placement controls, or open Frame Placement to decide what stays in view.
  • Switch to Fit Inside when edge content matters more than filling the frame.

Troubleshooting: If important content is cut off, move the visible area, use Frame Placement, or choose Fit Inside.

06

Keep Scale

Keep Scale keeps the final output dimensions fixed while letting you choose how much of the source image is sampled into that output.

  • Frame handles do not change the exported width and height.
  • Handles change the source area used to render the exact New Size.
  • Use it for ad slots, app screenshots, fixed layout frames, thumbnails, and production assets where output size must not drift.
  • Use Center or Reset when placement has moved away from a predictable default.

Example: A 1200 x 628 ad slot must stay exact, but the source crop needs more background. Use Keep Scale and adjust the sampled source area.

07

Frame Placement

Frame Placement gives you a larger precision workspace for exact-output image work.

  • Use the large preview when small placement changes matter.
  • Horizontal and Vertical sliders move the visible area precisely.
  • Zoom magnifies the workspace without changing export size.
  • Center recenters the current visible area. Reset restores default placement and crop scale.
  • Drag Image or Export Image from the placement window when the composition is ready.

Troubleshooting: Zoom changes what you see, not what exports. Use crop handles, placement sliders, or dragging to change the rendered composition.

08

Batch Workspace

Batch Workspace resizes and exports multiple images or folders as safe copies. Review the Images, Adjust, Name, and Export steps before any files are written.

  • Choose or drop multiple images or folders, then choose Batch Workspace for coordinated work.
  • Use Apply changes to This Image, Selection, or All Images before applying size, frame behavior, format, placement, or saved recipes.
  • Use Name to preview filename patterns and resolve conflicts, usually with automatic numbering.
  • Use Export only after reviewing warnings, names, destination, and readiness. ARC writes copies and leaves originals untouched.
  • Free users can inspect a batch. Batch edit/prep actions and exporting multiple image copies require ARC Pro Access.

Troubleshooting: If the batch is not ready, review crop, upscaling, format, or filename warnings before applying settings to a wider selection.

09

Copy and Developer Output

Copy tools are for handoff. Visible value chips copy exactly what they display.

  • Click a chip when you only need that displayed value.
  • Copy Output uses the selected output template, such as CSS, HTML, Tailwind, Markdown, or a saved custom template.
  • Custom templates are managed in Settings → Copy and can use variables such as {newSize.width}.
  • Saved custom templates are a Pro feature.

Troubleshooting: If copied output is not the expected format, select the desired template in the bottom picker and click Copy Output again.

10

Image Transfer

Choose, drag and drop, and paste load source images. Copy Image, Drag Image, Share, and Export Image use the rendered output.

  • Paste an image or image file with Command-V.
  • Copy Image places the rendered result on the clipboard.
  • Drag Image, or drag the loaded preview, to send a rendered file to Finder, browser upload fields, or another app.
  • Export Image writes the rendered result to disk in the selected format.

Troubleshooting: Drag Image uses the current size, frame behavior, placement, and format. Check the Preview before dragging.

11

Export Formats

Export format affects file type, transparency, quality controls, and background behavior.

  • PNG is a good default and preserves transparency.
  • JPEG/JPG is useful for smaller web and photo files but uses an opaque background.
  • TIFF is useful for high-quality workflows and can preserve transparency.
  • HEIC and HEIF availability depends on macOS ImageIO encoder support and destination compatibility.

Troubleshooting: If padding appears white instead of transparent, choose PNG or TIFF.

12

Units and DPI/PPI

Pixels are the app's canonical image unit. Other units are derived from settings assumptions.

  • Use pixel values as the source of truth for image dimensions.
  • Use rem, em, in, cm, mm, pt, vw, and vh values for web, print, and documentation handoff.
  • DPI/PPI affects print-style unit conversions. It does not change image pixel count.
  • Click visible chips to copy the displayed unit value.

Troubleshooting: If changing DPI/PPI does not change pixels, that is expected. Change New Size for a different pixel output.

13

Themes & Presets

Themes change the app workspace appearance, not exported image pixels. Presets help you return to known ratios and exact sizes quickly.

  • Follow System, Light, and Dark are available without Pro.
  • Use Settings → Themes to browse free themes, favorites, recently used themes, and branded workspace themes.
  • Blueprint Dark is included with Pro.
  • ARC Pro Access unlocks the bundled branded workspace themes and curated exact-size presets.
  • Favorites, Recently Used, ratio presets, and pack presets help avoid retyping common sizes.
  • Use Settings → Packs to browse bundled curated exact-size presets before adding the ones you use most.

Troubleshooting: If an exported image does not match the selected app theme, that is expected. Themes affect the workspace only.

14

Pro, Subscriptions, Mac Lifetime, and Support

ARC Pro Access, legacy purchases, and support purchases have different purposes.

  • Annual Pro and Monthly Pro unlock ARC Pro Access while the subscription is active.
  • Mac Lifetime unlocks ARC Pro Access for this Mac app only.
  • ARC Pro Access includes advanced app features such as custom copy formats, saved export recipes, batch export, advanced unit settings, iCloud Settings Sync, Menu Bar Hotkey configuration, bundled themes, and exact-size presets.
  • Support Development purchases are optional support for eligible legacy users and do not unlock features.
  • Restore Purchases refreshes Mac App Store entitlements.

Troubleshooting: A Support Development purchase does not unlock Pro. Use Annual Pro, Monthly Pro, or Mac Lifetime for feature access.

15

Accessibility

The app should stay usable from the keyboard, with VoiceOver, and in every supported localization.

  • The four core size fields use a predictable tab order.
  • Visible focus rings show which control receives keyboard input.
  • Placement controls expose labels, hints, sliders, and adjustable behavior.
  • Use sliders for precise placement when pointer dragging is too coarse.

Troubleshooting: If text feels cramped in a localized build or with larger text settings, use the default window size or a wider window and report labels that block understanding.

16

Help Search and Walkthrough

The Help Center is available from Help → ARC: Aspect Ratio & Resize Help. The walkthrough is available from Help → Show Walkthrough.

  • Search filters topics locally; no query is sent to a server.
  • Use terms such as crop, padding, CSS, DPI, theme, Pro, support, export, or walkthrough.
  • The empty state appears when no topic matches the search.
  • Settings → General includes controls for walkthrough and help prompt behavior.

Troubleshooting: If search shows no results, try a simpler feature word such as crop, frame, export, theme, or Pro.