which plug ins are the best to use to make images responsive and fast uploading?

The WordPress core handles this already. No plugin needed.

thanks,
I am using underscore_me Theme do I have to not worry about the right image sizes for the right device.
I am confused about src set picture property because there is a lot of formats of screens android itself has too many formats. and I want to automate this process.
the right format reolution for the right device can speed up the page upload.
I see there is imgix and other tools what it can be your advise to me?
imgix looks little wrapped.
I am trying to learn webdesign but because I am ill for years it is going little slowly with me.
johannes

You are contradicting yourself.
WordPress adds the correct srcset attribute. The browser loads the correct image according to the srcset attribute. You don’t need a plugin or theme to do it. It is already handled, in WordPress.

thank you,
but what about media cloud, imgix plug ins or services.
I know they offer CDN services but besides the CDN what are the benefit of it .
do you mean I don’t need those plug ins to do the work.
when I go to my testing and learning website :https://webdesignleren.com/?page_id=10
and click on inspect elements I don’t see any srcset code is this normal?
thank you again

Your example is using a plugin to serve the image from a CDN. That plugin bypasses the WordPress handling for srcset, which only works on images in your media library.
If you continue to use the plugin for the image CDN, you would need to ask at the plugin’s support forum about them handling srcset. If you remove that plugin, WordPress will do the srcset.

thanks for all usefull information,
1-I want to be clear so you tell me that wordpress automatically manage the images for every screen resolution from k2,k4 or for example every android resolution screen.
so I don’t need to take any third party plug in.
2-I have also 5 license smart slider 3 pro which I can use to manage images.what do you think about it?
3- where I can find in wordpress the srcset informations for images I use?
short answers wil be enough.
thanks
johannes

If you use the WordPress media library, you will have the various image sizes that you chose in the Settings > Media options and any others that plugins or themes have defined. These are used by WordPress to generate the srcset and sizes attributes. The browser itself is what chooses the correct image from the ones specified.

I have no knowledge of any slider code. I only know that sliders are a poor user experience, and are often not accessible to all users.

Are you looking for the functions that output the srcset? Or do you want the actual result (open a page and use your browser to View Source)?

thanks,
I make a search in google about support of responsive images in wordpress .
I see that wordpress creates some image sizes or srcset.
but what about wp retina2 plug in or ewwww image optimizer that some blog writers advise it to use .
do I not need those plug ins? wil wordpress wil be enough!
I have also smart slider3 pro shall I use this plug in to get most benefit of responsive images or wordpress wil be enough?
what do you advise me as a last answer.
johannes

Now you are mixing three different topics: responsive images, Retina, and image optimizing. They seem related, but are different.
You have to be careful when you search in Google, because the information could be accurate when it was written, but not necessarily accurate when you read it, since everything evolves, including WordPress.

Responsive images is about serving the file with just enough resolution for the device, so that it saves bandwidth and displays properly (the browser doesn’t have to upscale it and the image resizes with the window width).
Retina images have twice as many pixels in each direction, for use on high definition screens. It’s related to responsive images if you put srcset and sizes attributes to accommodate the larger width.
Optimizing images is about reducing the file size without too much damage to the resolution of the image. Humans mostly can perceive 72 dots per inch, and using more than that is a waste of bandwidth and file size.

I can’t tell you if you need a plugin. I’ve already told you what WordPress does. If your goals match what is already happening, then you likely don’t need additional code.

thanks
johannes