Support general aspect ratios auto for all shapes and square 1:1, circle 1:1, or other sizes like 4:1

There is Aspect ratio option named Fluid (auto sounds a better name, Fluid was taken from Fluid layout). It was meant for the deprecated custom multi-breakpoints image (#3105243: Shall we keep or drop custom breakpoints? Your vote counts) like Responsive Image, but output as IMG with SRCSET, not PICTURE.

Please clarify:

1. Are you using the provided option Aspect ratio as seen in the attached screenshot individually for each image? There are few options like seen in your screenshot: 1:1, 4:, 16:9, etc. If you do, you won't see the abrupt change from small to large like in that.
2. Does Fluid Aspect ratio work with non-PICTURE at your end? FYI, Aspect ratio with irregular sizes for picture is not working, yet.

Any improvement is very much welcome to the current limitation, of course.

Not related to your screenshots. As I saw you put images in grids, I just noticed there is a regression from RC3 for when any grid value is set to 1, likely for mobile version:
https://git.drupalcode.org/project/blazy/blob/8.x-2.x/src/BlazyGrid.php#L95
It should remove the condition that says && $settings['grid_' . $grid] > 1:

  if (!empty($settings['grid_' . $grid]) && $settings['grid_' . $grid] > 1) {
    $attributes['class'][] = $grid . '-block-' . $style . '-' . $settings['grid_' . $grid];
  }

Should be like RC3 without that condition:
https://git.drupalcode.org/project/blazy/blob/8.x-2.0-rc3/src/BlazyGrid....

  if (!empty($settings['grid_' . $grid])) {
    $attributes['class'][] = $grid . '-block-' . $style . '-' . $settings['grid_' . $grid];
  }  

Will provide a fix for this tonight, or so.

Thank you for giving the latest Blazy a whirl, Rajab. Truly appreciated.

If we have the Responsive image 1px placeholder + Image effect it will load them both
is it logical when we select Image effect to ignore the 1px placeholder?
Not very sure that it's overriding at this time

AFAIK, both uses the same SRC attribute, and the image effect is set to win. Having them both with says one, hence image effect, stored in a data attribute might need some extra work, which I can't afford for now. Aside from the fact that the image for effects can be very small below 50px. However patches are very much welcome. Thanks.

Aspect ratio with irregular sizes for picture is not working, yet.

I have added a temp fix for this with the latest commit today, so Aspect ratio Fluid should "work" with both Picture and regular Responsive image now, hopefully. I haven't thoroughly tested the fix against various setups so I might still miss anything.

The latest fix also makes it possible to embed Blazy (specifically related to the troublesome Aspect ratio Fluid which was previously broken) outside blazy-related plugins, hence without Blazy container, such Views Bootstrap, etc. The regular Views gotcha applies, checking or unchecking Use field template is normally the solution.

I am still working out few more TODOs before releasing a new RC, hopefully next week, if not sooner.

The Fluid or auto aspect ratio had been really tough works this far. It appears to work correctly in the past few releases, though. Not perfect due to Picture nature is different from regular Responsive image. Just works.

Closing this, unless anything else to do here. Thanks.