Hi Ismael,
I understand your thinking it shouldn’t spike CPU and if it does then it should only be when saving the post for the first time once and for the most part that is true, however if you are creating many posts then a host sees spikes and gets upset .
Then they block the account until you contact them so it causes issues and they dont care that it is wordpress default behaviour causing the cpu spikes.

The fact is that default wordpress has only 4 image sizes so default wordpress with only 4 image sizes doesn’t cause enough impact for it to cause too much pain, Enfold however kicks that up to 12+ image sizes “tripling” the impact of this problem and some of those added image sizes are HUGE,
This alone can be the kiss of death on shared hosting and gets worse when creating many new posts or importing bulk posts.

When themes add additional image sizes without considering the problem that the default core behaviour is too generate all images sizes for all images uploaded it makes a bad behaviour much worse.

I use enfold for client sites and this “too many images” issue is a constant cause of problems so I am asking for it to be addressed and considered as a real issue by Enfold Dev and in fact all theme devs. and rather than just saying it is a core wordpress behaviour and resorting to child themes and hacks and third party plugins perhaps as theme developers try to mitigate the issue as it currently stands to best of the themes ability with some controls and then also go to wordpress devs/support directly as popular theme developers and express to them why this behaviour is a bad core behaviour and push for them to address it as you guys have more weight than some unknown user.

Currently when people are asking about issues to do with images the common suggestions and replies are to use a child theme and make some change to either the image sizes by editing theme functions or adding css and then use the regenerate thumbs plugin or simple image sizes plugin to regenerate images which will in 90% of cases flatline a shared hosting account even on beefed up servers because those plugins go over all images in a post and generate all sizes at once which is if the issue was saving single posts causes CPU spikes then regenerating all images will definitely crash the server.
So in some cases the solutions offered make the problem worse by generating a massive load of new never to be used images thaat just consume even more hosting space and even further complicate future backups from completing.

If a theme is adding additional image sizes can it not somehow switch OFF the additional sizes that are optional or not necessary for default post types in the settings area and then have switches to turn on additional post types if they are going to be used by the user rather than recommending child themes and functions hacking and adding third party plugins ?

Why not take at least some responsibility as a theme and disable the uncommon unused and obscure sizes with some simple toggles within the theme settings area so that they are switched off by default and the user has to switch them on IF they are going to use those additional sizes.

for instance Enfold adds sizes for portfolio, if I am not a photography site I probably wont have a portfolio section and I am likely to never use portfolio image sizes so I don’t need the portfolio size images generated . Instead of generating them all by default when a post is created why not have them disabled by default and add a checkbox in theme settings to switch that size on if I intend to use the portfolio post types and want them on or have it off until I actually create a portfolio post type. Thus reducing/mitigating the potential issue somewhat. Same If I don’t have woocommerce installed – don’t have the shop sizes auto generated from images in a standard page or post.

Start off with light and fast in mind and add those heavier additional images only if they are needed and will actuality be used.

this would help mitigate the problem somewhat..
also if it is default wordpress behaviour exisits but is a bad behaviour then building a theme around that behaviour is compounding an existing bad behaviour, wouldn’t it carry more weight if popular theme devs such as kriesi aproached and worked with wordpress devs to address the potential for these problems instead of ignoring the issues. Perhaps wordpress core devs arent aware of if being a big issue because they only have 4 image sizes and any unwanted behaviour is not so bad in default themes that only use those sizes .. So theme devs that add sizes would be the best people to address the issue to the core devs aren’t they?

I cannot be the only wordpress user that sees how wasteful and disruptive it is to generate EVERY image size for EVERY image that gets uploaded.

how does switching hosts fix the issue ?
this wasteful activity is occurring by default on all images and post types and not only puts additional strain on the server but bloats the hosting space making backups take longer to complete if you are able to run a backup successfully at all, and due to too many innodes (too many files) 3rd party backup services such as I use provided by managewp simply fail because the uploads directory exceeds capacity of those backup services.
Moving hosting services so that the hosting account can better accommodate the problem instead of asking for core and theme devs to please understand this behaviour is hurting smaller hosting accounts and is just wasteful behaviour that can only lead to more trouble and support issues than are necessary seems better than just spending more money or larger hosting and larger backup plans.

Too many images being generated causes many performance problems on top of the obvious annoying issue of wasted hosting space and painful backing up and over time the issue gets worse as more images are constantly added into the equation so you will have to constantly upgrade hosting and backup plans as it gets more bloated.
The problem will become very evident if you ever need to move your site and have to transfer a massive uploads directory so you decide to reduce it in size and discover you have 20x versions of every image found in every post type you have made in the past 5 years or more (nightmare)..
I think the only answer is for theme developers whos themes add additional image sizes to wordpress to put some controls into the theme settings regarding their additiaonl image sizes and rather than have all images being generated for all post types it would be better to have by default NO images generated at all other than the featured “thumbnail” and any sizes that specific post type requires and any other image sizes are only generated depending on if they are needed in that Specific Post Type..
EG: woocommerce product page only generates the woocommerce image sizes required and does NOT generate portfolio sizes (for instance)
AND a portfolio post type only generates the Portfolio size images and does not generate woocommerce size images… etc etc
AND there needs to be prevention to only create those sizes for the first featured image NOT for image 2,3,4,5,6,7 etc

And for other sizes let the user have some control in the theme settings area to simply switch them on and off
so they are more aware of the image sizes taking up space or not.
additional control allowing us to not only switch a specific size off but also to delete all previously generated images of that specific size would be helpful also. eg if I have NO portfolio pages, let me delete all portfolio image sizes that have previoously been generated without having to use third party plugins that will generate EVERY THUMBNAIL at EVERY SIZE and crash a server.

Again though there are 3 important questions here that first need to be answered
1) why are all image sizes for all post types being generated instead of just those sizes required for the specific post type ?
2) Why are additional images in the body of a post having all additional image sizes generated when they wont ever be called for ?

and the big one : Can the theme settings provide us with control over this behaviour?

Bump
hello, is anyone here?

here are some screenshots demonstrating the issue on the homepage for the Recently viewed products widget and the main product catalog images.. expected sizes are 300×300 for catalog and 100×100 for widget thumbnails.. as shown they are various sizes.

next is images displayed in the footer area that are using the new products and top rated widgets
again note images of various sizes and none 100×100

here is the child theme quick css.. (was also present in main theme)

here is child modified functions

here is woocommerce customizer settings

and finally here are image settings according to simple image sizes plugin (yes after they have been regenerated)

thanks

Thank you so much Ismael!

We will use the plugin that will set the first image used in a post as the feature image, the code you gave stops the feature image from displaying in the post so we don’t get a double up while still allowing the feature image to be displayed in all our post sliders.

Thank you very much for all your time and help.
Cheers

Thanks Devin
We have got around it for now by increasing memory limit to 500mb and CPU to 50% of 2 cores. Everything now loads normally for now but its still using up to 250mb so we will keep looking into it.