How do I adjust the Proportional relationship?

You should be able to simply drop the 480 by 360 proportion in the proportional relation box like so: 480:360

The box “slideshow’s height” I leave empty?

The “Slideshow’s height” box should not be visible if the “Shrink slideshow’s height when width shrinks” setting is set to “Yes”. If this setting is indeed set to “Yes”, you could simply leave the “Slideshow’s height” field empty and set the “Proportional relationship” setting to “480:360”

Now it’s proportional, but the image is resized to 640×480 and I want you to be 480×360.

See the example online: https://www.tucuruiense.com/teste/

I want to be like: https://www.tucuruiense.com/sespa-investiga-se-virus-h1n1-causou-morte-de-mulher-em-tucurui/ with the image centered in this way.

My panel settings plugin are as follows:

Animation settings

Animation used for transition between slides [Slide left]
Number of seconds the slide takes to slide in [1]
Number of seconds the description takes to slide in [0.4]
Seconds between changing slides [5]

Display settings

Number of slides to fit into one slide [1]
Maximum width. When maximum width is 0, maximum width is ignored [0]
Proportional relationship between slideshow’s width and height (width:height) [480:360]
Slideshow’s height [empity]
Fit image into slide (Stretch image) [Yes]
Shrink slideshow’s height when width shrinks [Yes]
Enable responsiveness (Shrink slideshow’s width when page’s width shrinks) [no]
Show title and description [Yes]
Hide description box, pop up when mouse hovers over [Yes]

Control settings

Automatically slide to the next slide [Yes]
Return to the beginning of the slideshow after last slide [Yes]
Pause slideshow when mouse hovers over [Yes]
Activate navigation buttons [Yes]
Hide navigation buttons, show when mouse hovers over [no]
Activate pagination [Yes]
Hide pagination, show when mouse hovers over [Yes]
Activate control panel (play and pause button) [no]
Hide control panel, show when mouse hovers over [Yes]

Miscellaneous settings

Randomize slides [no]
Avoid content filter (disable if ‘!slideshow_deploy!’ is shown) [Yes]

Default Slideshow Stylesheet

The style used for this slideshow [Light]

I’m missing on something?

If you want the slideshow to be no wider that 480 pixels, you should set the “Maximum width” setting to “480”. You can then center the slideshow by following the instructions in this thread.

Hello friend, you gave the topic as solved but not solved.
I want the slideshow is the size that the example on this page: https://www.tucuruiense.com/galeria/

Is there any possibility of getting this size? How?

As I said, you should set the “Maximum width” setting to 480 to make the slideshow the size you want.