Image file size

  • As I develop my site, I will need to use different size images – generally I will display images 1200 x 800, 900 x 600 and 300 x 200. (Those resolutions are not fixed in stone!). The same image may be available in one or more sized version.
    The question is whether or not there is a lot of point in creating a version of each size for these multi use images? Can I just reduce all my images and upload 1200 x 800 sized versions and use those for whatever resolution it will ultimately be displayed at by editing in WordPress?
    In the bad old days of internet speed measured in Kbytes, it was essential to minimise file size as much as possible. Is it still necessary to minimise file sizes (other than reducing them to a few Kbytes rather than the original Mbytes size?

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  • Hi @begadoc,

    I think it’s still considered good practice to compress those images before uploading (although WordPress does do some of the compression work for you too).

    I would go ahead and upload just the reduced 1200×800 versions (or whatever ratio you decide to go with)

    Thread Starter begadoc

    (@begadoc)

    Thanks. I should have said that although I was hoping to stick to one resolution, I would be compressing as much as I could reasonably do.

    Moderator bcworkz

    (@bcworkz)

    You can define custom image sizes for WP to use. Then when you upload an image, WP will automatically create all the different sizes registered (smaller than the upload).
    https://developer.www.ads-software.com/reference/functions/add_image_size/

    The resize behavior is by default limited to crop or don’t crop, but you can add custom sizing logic through filter hooks. For example, I added a size that downsizes to the specified size using the longest image dimension, whether it be landscape or portrait (usually it resizes to width regardless of orientation).

    The other advantage of doing this is the different sizes then are included in the image srcset and sizes attributes so mobile browsers can fetch the most efficient size for their screen. Because of limited bandwidth of some mobile connections, image size is just as important as it ever was.

    Thread Starter begadoc

    (@begadoc)

    That’s a useful function I wasn’t aware of – like a lot of things in WP! Thanks.

    Moderator bcworkz

    (@bcworkz)

    Yup, so much to know, no one person can know it all. The funny thing is that mysterious unknown function often turns out to have the most obvious, intuitive name ??
    You’re welcome.

Viewing 5 replies - 1 through 5 (of 5 total)
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