Right size and compression level
Image sizes depend on what „Media Position“ you will use. In order to upload photos to your website you should reduce the weight and scale the image from the original, picture.
Never upload an original image.
This is an example of two photos in WordPress.
The info is:
File sizes are 872KB / 3MB → the sizes must be between 80 – 150 KB
Dimension: 3840 x 2560 px ratio:3840/2560=1.5 and → The size is too big you can use a 1000px x 667 px ratio=1000/667=1.5. Yes different size but the same ratio.
File name: iStock0.jpg → better a name that describe the post or page example “entrepreneur-conference.jpg”
Title: entrepreneur conference
Alt name: For SEO optimization we need the alt, this can be the same as the title.
Title = Alt Text: entrepreneur-conference
This wordpress installation have a plugin EWWW Image Optimizer for image optimization, but you always have to do optimizations before uploading the image to your site and don’t leave this work to the plugin.
The rule is to have the same proportion in all the pictures (ratio). It means the proportion between the width and the height of the image.
Recommendations for photos
Option1: „Full Width“
You want to put pictures that occupy the entire screen wide.
For „Full Width“ the minimum image size is between 1600 pixels width.
For this kind of photos we recommend you to use photos between 100KB and maximum 150KB.
Option 2: For „Inside the Content, Galleries, pages“
The size could be 800px width (it displays a medium image) or 1000 pixels width (it displays a large image with a better quality) wide, it depends on the quality of the photo. In this case use the pictures between 40kB and maximum 100KB.