Comparison

iMark · Image Annotation Tool vs OpenCat

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

iMark · Image Annotation Tool

Enhance and annotate images with a comprehensive set of tools. Import from your photo library, camera, or maps, and customize your markups with various styles. Easily export and share your creations.

Highlights
  • Diverse annotation tools (arrow, text, mosaic, etc.)
  • Import from photo library, camera, and maps
  • Customizable color schemes and history sessions
  • Crop and layer management
  • Export with custom image size
  • Supports iOS Photo Extension
Features
Read full description

iMark is a simple & powerful image annotation tool. iMark supports various tools & styles. You could import photo from photo library, camera & map. · All Tools You Need: Arrow, Rect, Circle, Text, Magnifier, Mosaic, Pen, Spotlight · Create annotations from photo library, map or empty canvas · Easy Export: Export with custom image size. Share with your friends. · Customize: History sessions, custom color schemes, redo & undo action. · Advanced Feature: Crop & Layer Management · Supports iOS Photo Extension · Supports Home Screen 3D Touch Quick Action · Supports iPad Multitasking

About

OpenCat

This AI utility tool offers seamless integration of advanced AI models into your daily routine on Mac, iPhone, and iPad. It features a user-friendly interface, keyboard extensions for in-app AI access, and Siri/shortcut integration for automation. Supports a wide range of popular AI models and offers team deployment options.

Highlights
  • Support for latest popular AI models
  • Keyboard extensions for in-app AI
  • Realistic voice synthesis
  • Siri and shortcut integration
  • Team deployment with Docker
  • Customizable AI parameters
  • Markdown content rendering
Features
Read full description

Bring AI into every part of your workflow: chat, writing, translation, and search. · Multiple model options — local models, API Key, Cloud subscription, Apple Intelligence · MCP — supports MCP and tool calls · Web search — available on OpenCat Cloud and select providers · System-wide translation — select text in any app for instant AI translation · Content rendering — supports LaTeX formulas, Markdown, and code highlighting · Cross-platform — natively built for Mac, iPhone, and iPad · Data privacy — stored locally, synced across devices via iCloud [Pro Features] · AI Keyboard — invoke AI right in the text field of any app to polish or reply in one step · OpenCat Cloud subscription provides access to all major models [A Variety of Models] · OpenCat Cloud — fast access to leading models · Local models — one-tap download of open-source models for offline use, accelerated by Apple silicon · BYOK — use your own API Key, including Coding Plan · System models — supports Apple Foundation Models [OpenCat Cloud — Ready to Use, No Setup] · No sign-up, zero configuration, all major models supported · 50+ models — ChatGPT, Claude, Gemini, Grok, DeepSeek, GLM, MiniMax, Kimi, Qwen, Doubao, and more, all in one place · Online search supported [System-Level AI Translation] Set OpenCat as your default translation app to translate selected text directly in Safari, Mail, Notes, and any other app. Powered by large language models, translations are natural and fluent — far superior to traditional translation engines. [Local Models, Offline Inference] · One-tap download — popular open-source models like Llama, Qwen, and Gemma · Apple silicon acceleration — built on Apple's official MLX framework, fully leveraging GPU performance for fast, energy-efficient inference · Fully offline — works without internet, conversation data never leaves your device [Use Your Own API Key] · 25+ providers supported — OpenAI, Claude, Gemini, DeepSeek, Kimi, Qwen, Doubao, ERNIE, and more [Contact Us] Email: support@dreamoon.ai Terms of Use https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy & Third-party AI Service Privacy Policy https://opencat.app/privacy

Screenshots

iMark · Image Annotation Tool4 screens
OpenCat4 screens

Verdict

The call

The clearest difference is update cadence: OpenCat at weekly against iMark · Image Annotation Tool's every 2 months. iMark · Image Annotation Tool's advantage is iOS requirement (13.0 vs 17.0). On price, rating, review sentiment and ratings volume there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. iMark · Image Annotation Tool sells 4 one-off in-app purchases and OpenCat sells 4 in-app purchases, starting at $3.99 per month. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.6 for iMark · Image Annotation Tool against 4.6 for OpenCat. Both are backed by a comparable volume of ratings — 384 and 855 respectively. Written reviews are what separate them: 72% of iMark · Image Annotation Tool's written reviews are positive against 65% of OpenCat's.

UpkeepUpdate frequency

iMark · Image Annotation Tool ships an update every 2 months, OpenCat weekly. The most recent releases landed on November 2, 2026 and November 7, 2026 respectively.

Scorecard2 real differences · 8 level
iMark · Image Annotation Tool versus OpenCat: the parameters behind the verdict, then further details
ParameteriMark · Image Annotation ToolOpenCat
PriceFreeFree
Rating4.6 (384 ratings) — better4.6 (855 ratings)
Positive reviews71.7% of reviews — better64.6% of reviews
Number of ratings384855 — better
Update frequencyEvery 2 monthsWeekly — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPad, iPodiPhone, iPad, Mac
Requires iOS13.0 — better17.0
Further details — not scored
Size93 MB96 MB
Age rating4+17+
DeveloperiDaily Corp.Early Moon, LLC

Customer experience

iMark · Image Annotation Tool

All ratings381 ratings
Positive90.0%
Neutral3.1%
Negative6.8%
Written reviews212 reviews
Positive71.7%
Neutral6.6%
Negative21.7%

OpenCat

All ratings855 ratings
Positive91.1%
Neutral2.2%
Negative6.7%
Written reviews195 reviews
Positive64.6%
Neutral11.3%
Negative24.1%

User reviews

iMark · Image Annotation Tool

From 384 App Store ratings

What we love

  • 👍 Intuitive and easy-to-use interface
  • 🎨 Comprehensive annotation tools (arrows, shapes, text, magnifier)
  • 💰 Completely free with no ads
  • 🎯 Powerful features for screenshot markup
  • 🔧 Customizable colors and styling options

Room to improve

  • 💧 Persistent watermark on all saved images
  • 🌐 Language defaults to Chinese with difficult switching
  • 📝 Text size limitations on large images
  • 🎨 Limited font customization options
  • ⚙️ Text bubble tail control is limited

OpenCat

From 855 App Store ratings

What we love

  • 🚀 Fast and responsive
  • 👍 Convenient and user-friendly
  • 💡 Customizable API integrations
  • 🌐 Syncs across devices
  • 🎨 Clean and visually appealing design

Room to improve

  • 🐛 Bugs and performance issues
  • 🔒 Lack of custom API support
  • 💻 Compatibility issues with older devices/OSes
  • 🗂️ Difficulty managing conversations
  • 📤 Inability to export chat data

Bugs and requests

iMark · Image Annotation Tool

Reported bugs

8 issues
  • App crashes when using brush/pen features
  • Export button hidden by system UI
  • Annotations disappearing after one day
  • Keyboard engagement obscures image during text input
  • Magnifier tool functionality issues
Show 3 more
  • In-app review text not visible while typing
  • Slow performance with multiple markups
  • UI elements not accessible (white buttons on white background)

Requested features

18 requests
  • Ability to remove watermark (paid option requested)
  • Multiple language support with easy switching
  • Filled/solid geometric shapes
  • Curved arrows instead of straight only
  • Multiple font selection from Google Fonts
Show 13 more
  • Text formatting (bold, italic, underline, strikethrough)
  • Opacity/transparency control for colors
  • Redaction/censoring tool for sensitive information
  • Thinking bubbles with text capability
  • Counter/numbering feature for annotations
  • Copy/duplicate annotation elements
  • Dark mode theme option
  • Ability to import multiple images as layers
  • Thinner line options for shapes and tools
  • Rounded rectangle shape option
  • Magnifier with square frame option
  • Undo/redo history management
  • Separate watermark and signature settings

OpenCat

Reported bugs

6 issues
  • Streaming response disruptions
  • Disappearing API key input fields
  • Inconsistent Markdown rendering
  • Keyboard extension not working as expected
  • Sync issues between devices
Show 1 more
  • Crashes and freezes when handling large inputs

Requested features

7 requests
  • Support for more AI models (e.g., Ollama, Groq)
  • Markdown rendering for chat responses
  • Ability to upload images and files
  • Customizable keyboard extensions
  • Background task support for long-running queries
Show 2 more
  • Prompt library and sharing functionality
  • Integration with other productivity apps (e.g., Shortcuts)

In-app purchases

4 purchases

iMark · Image Annotation Tool

One-time4
  • Coffee$2.99
  • Silver Coin$5.99
  • Gold Coin$14.99
Show 1 more
  • Coffee for Everyone$29.99
4 purchases

OpenCat

Subscriptions2
  • Cloud AI3 Days trial$3.991 Month
  • Cloud AI$24.991 Year
One-time2
  • Tokens Package$5.99
  • OpenCat Pro$9.99

Questions

Is iMark · Image Annotation Tool free?
iMark · Image Annotation Tool is free to download, with in-app purchases available.
Is OpenCat free?
OpenCat is free to download, with in-app purchases available.
Which has better reviews, iMark · Image Annotation Tool or OpenCat?
iMark · Image Annotation Tool is rated higher. iMark · Image Annotation Tool averages 4.6 out of 5 from 384 ratings, while OpenCat averages 4.6 from 855 ratings.
Do iMark · Image Annotation Tool or OpenCat have ads?
Neither iMark · Image Annotation Tool nor OpenCat shows ads.
Which is updated more often, iMark · Image Annotation Tool or OpenCat?
iMark · Image Annotation Tool ships an update every 2 months, and OpenCat weekly. Most recently, iMark · Image Annotation Tool was updated on November 2, 2026 and OpenCat on November 7, 2026.

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