Lessons
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Introduction
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Search engine optimization
- Broken links
- Site map
- Micro-markup
- Robots.txt
- References
- Text
- Duplicates
- Basic
- Pictures
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Speed
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Minification
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CSS minification
Minification of JavaScript files
Minification of inline CSS code
Minification of images without loss of quality
Minification of JavaScript files
Unused CSS code
Data optimization:Image URLs
Format of animated images
Unused JavaScript code
Using WebP
Image compression is missing
Video bitrate
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Reducing requests
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An overabundance of small pictures
Ungrouped CSS files
Ungrouped JavaScript files
An overabundance of fonts
Availability of end-to-end CSS, JS files
The presence of a monochrome font
Uploading duplicate files
Using JS facades
Redirecting JavaScript code
Adding lazy loading
Redirect from/to www version
- Fonts
- Loading time
- Server Settings
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Pictures
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The original and displayed size of the images
Using sprite technology
Recompressed images
Cropping Images
- The first content
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Minification
- Mobility
- Bugs
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Convenience
- Social networks
- Web Application Manifest
- Favicons
- Basic
- Text readability
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Security
- Encrypted connection
- Exploits
- Vulnerabilities
The original and displayed size of the images
The original image file located on the server? It has its own size, and the block on the page in which it is displayed has its own size. In order for the images to look clear on the screen, these sizes must match. If the size of the original image is larger than the displayed one, which means it should be reduced to save time downloading the file.
4k monitors and mobile devices have several screen pixels corresponding to each pixel on the page. The ratio of country pixels to screen pixels is called device pixel ratio or DRP.
For high-resolution screens, we recommend using images with a DPR equal to 2. Some phones are capable of displaying images with a factor of both 3 and 4 DPR, but then the images will be too heavy and will greatly delay page loading. Double—precision images (DPR equal to 2) are the perfect compromise.
We are testing a page on a 414 pixel screen. But smartphones range in size from 360 pixels to 430. Of course, it is impractical to make an image for each screen size, so we selected the most optimal size for our verification service at 414 pixels [based on statistics] (https://gs.statcounter.com/screen-resolution-stats/mobile/worldwide ). The use of screens larger than 414 pixels is about 5%.
The appropriate size of the images is important for the following reasons:
- Users of 4K monitors see high-quality pictures. And this is the most solvent audience.
- Reducing the size of images, therefore, speeding up page loading.
Read the same:
- Database of all screen resolutions [https://yesviz.com/viewport /](https://yesviz.com/viewport /). Information about your screen [https://www.mydevice.io /](https://www.mydevice.io /).