The
OP , although apparently asking a very specific question that seems repetitive, is a wave with advanced users or those who like to incorporate "1000 more words" with an image to their publication.
I suspect that he is a user who frequents the sites that "resize" the photos, so common that when they come to a forum like bitcointalk.org it seems impossible. It is not that this is uncommon, e.g. in Steemit, a simple command is required for very basic things.
That said, let's "dismember" your questions:
... Could someone help me what exactly is the size of the images to post in thread?
No. How to know exactly! each post is personal-individual.
Here we enter the topic of suggestions and that is why I take your post, because in the general sense several responded and some answers are helpful.
One of the reasons that I answers, that you cannot specify what the size is, it depends on the objective of the image in the post:
If it is a header it should be a 700x200 or 700x450 photo. Specifically, standard photos that come with a size ranging from 1280x720 are used.
Why not use bigger or smaller ones; small it is obvious that a photo that starts a publication does not look good,if you are targeting a message.
The image does not contribute do not use it, in a forum like this the images should contribute to the content not decorate.
Contribution example:
https://bitcointalk.org/index.php?topic=5235794.msg54802650#msg54802650Decoration example:
https://bitcointalk.org/index.php?topic=5256096.msg54632811#msg54632811In your OP you mention something important "... Suggest me the best
size and resolution for image."
If you try to use a very low resolution image and want to enlarge it it looks bad, they say "pixelated." The example in post # 4 of mk4, is the best example from its original size to a smaller one, nothing happens, but if the resolution is low when enlarged it is distorted.
[img height = 600]https://bitcoin.org/img/icons/opengraph.png[/img]
So keep in mind the resolution of a photo if you want to resize it.
Another important thing is using the
![](https://ip.bitcointalk.org/?u=https%3A%2F%2Fi.imgur.com%2FUtWkagj.png&t=663&c=-8kG9aCRAWV3Vw)
button, that gives you an idea of how it will look, keep in mind, that the size of your monitor may be not average, that is, you either use a very large monitor or work from a table. (I would never try this from my cell phone;) )
Finally, the above can serve as an example of two additional uses that I can "suggest" of use in size and resolution.
Additional:
The use of images is limited to going alone on one line, you cannot include text on the right or text on the left.
I tried to use this command:
[imtext =] would be an explicit ornament in a post [/ imtext]
There is additional code that works over html, but that option is locked.