Image Quality
What determines image quality, how quality interacts with file size, and how to choose the right quality settings for screenshots and exports.
Image quality has two meanings. One is how faithfully an image shows its subject: sharpness, color accuracy and the absence of artifacts. The other is the quality setting of a lossy encoder, a number that controls how much detail compression may discard.
The encoder setting is not a percentage of retained data. In JPEG encoders based on libjpeg, a value from 1 to 100 scales the quantization tables. The same number gives different results in different encoders and formats, so quality 80 in JPEG and quality 80 in WebP are not equivalent.
Quality can be measured with metrics such as PSNR and SSIM, but a zoomed visual check is the practical test for screenshots.
Convert image formats
Format choice sets the ceiling for quality. Convert between PNG, JPG and WebP with Image Converter.
What determines image quality
- Pixel count: more pixels hold more detail, which is why Retina captures look sharper.
- Compression: lossy settings remove detail and add artifacts.
- Scaling: downscaling by odd factors blurs thin lines; upscaling cannot add detail.
- Color handling: a missing or wrong color profile shifts colors.
Quality vs file size tradeoff
File size falls quickly as the quality setting drops from 100, while visible change is small at first. Below a point that depends on content, artifacts appear: blocks in flat areas, ringing around text and banding in gradients. Screenshots with small text reach that point sooner than photos.
Quality settings in export
| Temposhot export | Quality control |
|---|---|
| JPG Export (Adjustable Quality) | 1-100, default 85 |
| Auto Export (Save as you go) JPG | Default 85 |
| Website Capture JPEG and WebP | 1-100 |
| MP4 | High, Medium, Low |
| PDF dialog (Pro customization) | Image sizing and quality |
PNG Export (Lossless) has no quality setting because it does not discard data.
Common mistakes
- Setting quality to 100 and expecting lossless output. JPEG at 100 is still lossy.
- Comparing settings at different zoom levels.
- Judging quality on a Retina screen only, where artifacts are smaller.
- Re-saving a JPG several times at moderate quality.
Have an image to fix right now?
Compare two exports side by side with Compare Images, or reduce a file with Image Compressor.
Common questions
What quality should I use for screenshots?
Start at 85. Lower it in steps and compare a zoomed crop of small text until artifacts appear.
Does a higher resolution always mean higher quality?
No. A large image saved at low quality can look worse than a smaller image saved well.
Sources
Related resources
- Export formats: image, PDF and MP4 settings.
- Documents export: PDF image sizing and quality.
Taking the same screenshots again and again?
Temposhot captures a screen, window or area on a timer and exports the set as a PDF, images, ZIP or MP4. The free browser tools fix single images.
Related resources
Related terms
- Lossy CompressionWhat lossy compression is, which image formats use it, and how to balance file size against visual quality.
- Image CompressionWhat image compression is, lossy vs lossless explained, and common mistakes when compressing screenshots.
- JPGHow JPG compression works, when to use it vs PNG and WebP, and common mistakes with lossy screenshot formats.
- Screenshot ResolutionA screenshot copies the pixels on screen, so it doesn't lower quality by itself. See what makes screenshots blurry and what decides their size in MB.
- DPIWhat DPI means for screenshots, how it affects resolution and file size, and common confusion with PPI.
- Lossless CompressionWhat lossless compression is, which image formats support it, and when pixel-perfect preservation matters.