You are welcome.
Here are the answers to your questions:
[Will all subsequent uploaded images be given size attributes by this plugin if they are not specified via CSS?]
Whether the size attributes are specified via CSS or not, size attributes will be added automatically in run time.
[Will size attributes later added via custom CSS override the plugin’s added attributes?]
Yes, custom CSS values will override the plugin’s added attributes.
[What happens to the attributes added by this plugin if we decide to deactivate/delete the plugin?]
Since the size attributes are added in run time, deactivating/deleting this plugin will remove the size attributes that are being added by the plugin.
I hope these answers clarify your thoughts about the plugin.
Thank you for your prompt reply.
To clarify further, what do you mean by “run time”—do you mean when or if an image is uploaded?
In other words, what “triggers” or causes the plugin to “scan the entire page” for “images with missing width and height attributes”?
Is the plugin “scanning” all the time, in the background, using server resources?
You addressed a “server resources” concern in another thread saying, “This plugin didn’t take much of the server resources.”
Please be specific as to when the plugin runs.
It seems like it would be a waste of server resources if the plugin was running all the time, constantly scanning for image attributes, especially when the missing attributes have already been added previously by the plugin itself.
The plugin works in this way; when an HTML page is generated in response to a request from the user, the plugin scans the generated HTML page and adds width and height attribute only to those images for which these attributes are missing.
Which means this plugin only works when a page is requested.
This plugin does nothing when an image is uploaded because width and height attributes are not added at that time. These attributes are added/should be added when an image is being added in a post or page. WordPress adds theses attributes automatically if you add the images using WordPress media library but if the images are added by some other medium (e.g. plugin, theme or hard coded etc.) and that does not add width and height attributes then this plugin comes handy.
