Image size, optimisation and compression question

Hi there,
I'm confused about image optimisation & size for my WordPress blog.
In the Smush FAQs there are 2 questions - see attached. In the first it says that Smush optimises 'cropped and resized images' only in Wordpress i.e. it does not compress/optimise "all" the images you upload to WP?? In the second FAQ it says that it optimises "all" WP images... Which of the statements is true?
- I want to upload 600 large images to my WP blog. Some are landscape and some portrait. If I import these via Smush, will all these images be optimised on the way into WP?
- I see there is the option to give a 'max size' in pixels for images coming into WP. Can you tell me what the best 'size' would be for portrait and landscape images please? At this stage I am not sure whether the images will end up as a 'full page' width or as a thumbnail size in the blog, so bearing this in mind, what is it best to go with (portrait/landscape)? Wordpress were unable to answer this question - they recommended I ask Smush instead.
Many thanks for your help.

  • Jordan

    Hello Julie,

    I understand your confusion and I'll try my best to make it clear.

    Whenever you upload an image to WordPress and WP-Smush is activated, your image will be compressed and optimized automatically but the original file you uploaded is not affected. Essentially, when you upload it WordPress generates multiple versions of your images for different sizes for embedding/inserting into your site, it is these that are optimized. This way you still have your original image.

    If you want to cut down on space there is an option to resize your original images.

    As for your images you wish to upload, all of them will be optimized upon upload.

    In regards to the image size this depends on how your website was designed. The important thing to do is to maintain the aspect ratio of the images to ensure they aren't distorted. Also do take in mind that if you have a global max image size it affects all images, not just your featured post images. I think someone else will have to advise you on this question.

    Hope this helps.

    Thanks,
    Jordan.

  • Predrag Dubajic

    Hi Julie,

    Hope you're doing well :slight_smile:

    Jordan has some good points (thanks for jumping in again Jordan :slight_smile: ), but I do have a couple of things to add :slight_smile:

    First thing is that you're referring to FAQ from Free Smush version and there are differences between free and pro versions and what they can optimize.

    As Jordan already mentioned, when you upload a new image to WordPress it will upload the original image and additionally create smaller thumbnails of that image, there are couple thumbnails defined by WP itself, and your theme and plugins used can define more of them as well.

    Full-size image is rarely used as themes and plugins would usually use their registered thumbnails in order to reduce page size, and optimization of full-size image is not available in Free version.
    However, in Pro version of Smush you can also optimize full-size images, all you need to do for this to happen is go to Media > WP Smush and enable "Smush my original full-size images" option.

    - I want to upload 600 large images to my WP blog. Some are landscape and some portrait. If I import these via Smush, will all these images be optimized on the way into WP?

    With the above thing explained, the short answer to this is yes, all your image will be optimized.

    - I see there is the option to give a 'max size' in pixels for images coming into WP. Can you tell me what the best 'size' would be for portrait and landscape images please? At this stage I am not sure whether the images will end up as a 'full page' width or as a thumbnail size in the blog, so bearing this in mind, what is it best to go with (portrait/landscape)? Wordpress were unable to answer this question - they recommended I ask Smush instead.

    I can't really give you an exact answer to this as it mainly depends on your setup itself, theme and plugins used, as well as your own desired image size.
    Thing to note is that resizing option will not distort your images, it will keep the original ration and it will resize it based on the larger image side.
    For example, let's say you set the resize option to 1000x500 pixels, if you upload an image that's 2000x1600 you will not end up with full-size image of 1000x500 but rather it will be 1000x800, so it catched the larger side and adjusted image based on that.

    Important thing to check is what's the largest thumbnail used on your site, you can see all sizes your site creates when you go to Media > WP Smush, and then make sure that you don't set resized image smaller than the largest thumbnail.

    Hope this helps and let us know if you have any followup questions about this.

    Best regards,
    Predrag

  • Julie

    Hi Predrag,

    So have I understood this correctly? I upload an original image to Wordpress. That original image is not optimised unless I take a Pro subscription to Smush.

    Wordpress takes that image and creates several smaller images from it (at appropriate sizes for my Theme in my blog as per WP Smush > settings page)... so there will be the original image and say, 5 smaller versions of it. It is these 5 smaller versions which Smush optimises (with the free version).
    I have a few more questions:
    - Can I delete the original (large/un-optimised) image if WP has created the 5 smaller versions of it?
    - If I don't take Smush Pro, I should resize my images before uploading them to WP (because Smush won't optimise them)?
    - The best size to resize them to is the size of the largest thumbnail (or other sizes of image used in my WP theme??). My largest thumbnail is 1024w x 1024h and largest slider is 1920w x 650h. So what would be the best size to resize them to outside of WP if I decided not to go with Smush pro?
    - If I resize them to a generic size before uploading them to WP, how do I know what the aspect ratio should be?

    Many thanks,
    Julie

  • Predrag Dubajic

    Hi Julie,

    So have I understood this correctly? I upload an original image to Wordpress. That original image is not optimised unless I take a Pro subscription to Smush.

    Wordpress takes that image and creates several smaller images from it (at appropriate sizes for my Theme in my blog as per WP Smush > settings page)... so there will be the original image and say, 5 smaller versions of it. It is these 5 smaller versions which Smush optimises (with the free version).

    That is correct, just to be clear, during the Free Trial you also have Pro version options available just as the paid member.
    Of course, you just need to enable "Smush my original full-size images" option in Media > WP Smush panel.

    - Can I delete the original (large/un-optimised) image if WP has created the 5 smaller versions of it?

    This is not recommended because you might want to put original image sometimes, or perhaps your theme or one of the plugins requires it.
    Also, if you ever need to regenerate your thumbnails WP will need to have that original image in place.

    - If I don't take Smush Pro, I should resize my images before uploading them to WP (because Smush won't optimise them)?

    If you use the free version (not to confuse with free trial which is a Pro version) your original image will not be optimized, regardless if you resize it before upload or not.
    To make this more clear, let's say you upload image.jpg to your site, on your server you will end up with something like this image.jpg, image-150x150.jpg, image-300x300.jpg, image-750x250.jpg etc.
    Those with numbers are thumbnails created from your image and is what Free version of Smush will optimize.

    - The best size to resize them to is the size of the largest thumbnail (or other sizes of image used in my WP theme??). My largest thumbnail is 1024w x 1024h and largest slider is 1920w x 650h. So what would be the best size to resize them to outside of WP if I decided not to go with Smush pro?

    If your slider is 1920x650 then it's suggested not to upload images smaller than that because if you try to add a smaller image to slider it will probably be stretched to fill slider size and cause the image to look pixelated.

    - If I resize them to a generic size before uploading them to WP, how do I know what the aspect ratio should be?

    That depends completely on your site and how are you going to use the images.
    Aspect ration shouldn't really matter, if theme or plugin requires specific image size (both width and height) then it usually creates a thumbnail with cropping option enabled.
    So when you upload your image it will create the required thumbnail out of it.

    Otherwise, if cropping is not set, it will behave the same way as Smush's Resize Option that I talked about in my previous response.

    Hope this helps and that I didn't miss any question :slight_smile:

    Best regards,
    Predrag

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