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Image Responsive Preview
Upload one image and check how it scales on smartphone/tablet viewports from your PC. Includes font-size scaling hints for ad/LP checks.
Input
PC向け確認ツール: 画像はブラウザ内だけで処理されます。
ファイル: 未選択
画像サイズ: —
例: 1200（PCカンプ幅）, 1080（SNS正方形）
Preview
画像をアップロードすると、スマホとタブレットでの見え方を並べて表示します。
Font Size Scale Check
| Design Font | Phone 390x844 | Phone 412x915 | Tablet 768x1024 | Tablet 820x1180 |
|---|---|---|---|---|
| 48px | 15.6px | 16.5px | 30.7px | 32.8px |
| 32px | 10.4px | 11.0px | 20.5px | 21.9px |
| 24px | 7.8px | 8.2px | 15.4px | 16.4px |
| 16px | 5.2px | 5.5px | 10.2px | 10.9px |
判定目安: 16px以上 推奨 / 14px以上 最低可読。
Image Responsive Preview: Guide
- Intent
- Upload one creative image and preview how it appears on common smartphone/tablet viewport sizes before publishing ads or LP assets.
- What it does
- Shows your uploaded image inside multiple device-sized preview frames and calculates font-size scaling based on your design base width.
- Key features
- Phone + tablet viewport previews, Design base width control, Font-size scaling table, Local-only processing
- Privacy
- Runs locally in your browser. Uploaded images are not sent to a server.
- Best for
- Ad creative checks before campaign launch
- LP hero image checks for mobile readability
- Teams validating text size shrink on small screens
- Why this tool
- Fast visual check across multiple devices on a desktop workflow
- Numeric font-size scale estimates alongside visual preview
- No upload pipeline; quick iteration in-browser
How to use
- 1Upload your image file.
- 2Set the design base width (e.g., 1200 for desktop comps).
- 3Review phone/tablet frame previews.
- 4Enter key font sizes (comma separated) and check scaled px values.
Common mistakes
- Using the wrong base design width, which distorts scaling estimates.
- Treating this as a full browser/device emulator (it is viewport-scale preview).
- Ignoring safe areas/margins from ad platform templates.
Examples
LP hero validation
Image: hero-banner.png
Base width: 1200
Font sizes: 48, 32, 24, 16
Check if mobile scaled values stay above your readable threshold.
Ad creative check
Upload one ad image
Compare Phone 390 / Tablet 768 previews
Confirm headline remains legible before publishing.