Please help me understand image sizes

  • flizzywp

    (@flizzywp)


    8 years, 6 months ago

    Hello,
    i have trouble understanding image sizes in WordPress.
    I have a pretty wide layout so my featured image is pretty big. I have edited the source image to about the same dimensions and saved it as an .jpg.
    No problem so far.

    I use a plugin to show my posts in a grid. It’s called “Content Views” and has pretty good ratings. But i tested my site with a speed tester and it told me, that my thumbnail in this grid actually shows the whole full-sized image (just downscaled) and therefor slows down the speed. How can i change that?
    I read that WordPress generates different image files for different sizes, but i can’t find any of them. Where are they and where are they used? If i click on “Media Settings” and change dimensions there, it does nothing at all. Neither to the featured image, nor to thumbnails.

    Can anyone please enlighten me because this is the kind of stuff that gives me headaches.

    Thanks in advance,
    Florian

    The page I need help with: [log in to see the link]

Viewing 2 replies - 1 through 2 (of 2 total)
  • Jacob Peattie

    (@jakept)

    8 years, 6 months ago

    The alternate sizes are saved in wp-content/uploads alongside the original image. They will be suffixed with dimensions like -150x150.jpg, for example.

    By default there will be thumbnail, medium, and large versions of the image. The dimensions for these are set in Settings > Media. Your theme might also register its own size for post thumbnails. Plugins and themes can also register additional sizes if they want.

    The sizes and which file they correspond to are stored in the _wp_attachment_metadata meta for the attachment post (each upload is represented in the database as an attachment-type post).

    Templates, whether they are in a plugin or theme, when given a particular image can choose to output a particular version. This would be to avoid the issue you’re having. So a theme might choose to use the medium version of the image so that the whole image isn’t loaded.

    Plugins, like Content Views, when outputting a selected image could just output the full size image, or it could output a cropped version. Either one of the default WordPress sizes, or one it registered itself. But that depends entirely on the plugin. If a plugin or isn’t outputting appropriate image sizes you’ll need to contact the developer to find out if there’s a reason or option to change the size.

    Another possibility is that you’re attempting to use a size that was registered after the image was initially uploaded. If Content Views is trying to use a size that it defined itself, but is trying to output an image that was uploaded before the plugin was activated, then it won’t be able to find the cropped version and will output the full size. This is because cropped versions are only made for sizes registered when the image was uploaded. To work around this either re-upload the image, or use a plugin like Regenerate Thumbnails to do a fresh pass on all you images.

    Thread Starter flizzywp

    (@flizzywp)

    8 years, 6 months ago

    Wow thank you for the long detailed answer. I will have to read it a couple times.

Viewing 2 replies - 1 through 2 (of 2 total)

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