Must be a language barrier. Posters are something you hang on a wall. Like a movie poster for example. What you're looking for is typically called 'slides' (this used to be done with overhead projectors).
No, it's scientific jargon. It's called posters.
No, LibreOffice Draw is the tool, not Impress.
beamerposter). If you prefer dragging text/image frames across the canvas, try a DTP program like print/scribus. You could even create posters with graphics/gimp3-app.
\documentclass[goettingen]{beamer}
\usepackage{beamerposter}
\usepackage[english]{babel}
% XeLaTeX stuff
\usepackage{fontspec}
\usepackage{xunicode}% has to be loaded after fontspec
\usepackage{xltxtra}
\usepackage[]{libertinus}% ensure x11-fonts/libertinus installed
% font stuff
\setmainfont[Mapping=tex-text]{Libertinus Serif}
\usepackage[protrusion=true,babel]{microtype}
\begin{document}
Happy Towel Day!
\end{document}In my picture, each slide is a posterDefinition of POSTER
a usually large printed sheet that often contains pictures and is posted in a public place (as to promote something); a usually large printed sheet that is put on a wall as decoration; a person who posts something online… See the full definitionwww.merriam-webster.com
Definition of SLIDE
to move smoothly along a surface : slip; to coast over snow or ice; to fall or dive feetfirst or headfirst when approaching a base… See the full definition
I'm just an undergraduate, and this is my first time to make a poster. I'm doing it for my advisor.
Nobody is going to give those blurry things a closer look. 
To process graphics use magic:
Well, yeah (good one) - but as exemplary the ImageMagick tools are (they are my standard tools), they cannot fill in the missing information when enlarging raster graphics.
When I did a poster presentation in college as an undergrad, I just used PowerPoint. And frankly, the important thing is not even the tool you use, but having an idea in mind, and what you want to show on the poster.
These slides were my professor gave me to make posters as referenceI'm not quite sure what you actually mean, since poster to me means a single large sheet - so if the graphics are already given, which was another question, the job was mostly to resize the graphics to fit the format.
If slides of a presentation are meant, then the quickest and easiest way to create a presentation I know, is as Espionage724 already said, using LibreOffice Impress ("Powerpoint").
There are also some other ways/progs to create presentations, like there are some LaTeX packages providing different ways for creating presentations, but if you are not already a well versed LaTeX user I wouldn't recommend that way for this project, since I guess there is not enough time to learn several tools plus LaTeX, plus learn how to make a good presentation slides, plus create the slides.
Old engineering wisdom:
You either do a new job with old tools (already well versed on).
Or you use new tools on an old job.
But never do a new job with new tools.
So, you better use well versed jobs as a chance to learn new tools, to enlarge your toolbox.
Graphics:
If the graphics are given, they are hopefully at high resolution or even better as vector graphics. The latter ones can be down- and upscaled without quality loss. Raster graphics (.jpg, .gif, .bmp,...) can only be downscaled at good quality.
To enlarge low resolution pictures Gimp provides a lot of tools to adjust picture quality. But don't demand magic. Besides the tools are not easy to use for newbies, enlarging a raster graphics means adding pixels - filling the gaps of missing information. You could try some AI based tool, but missing information stays missing information. All also any AI can only do is guessing what would fill the gaps between the pixels.
The "onboard" graphics editor of Powerpoint/Impress is more than quite sufficient enough for producing own graphics for presentations. Otherwise Inkscape was a good choice (question is again, which tools you already know to use.)
Anyway, the pictures you are showing are good for some poster, but they are (very) bad for a presentation - way too much information density; impossible for any audience to grasp while a presentation runs; except the slides are not meant to be shown while a presentation, but to study for anybody for themselves. Anyway I hope that's not the only quality you have, but there is (way) better, because they... - frankly: they suck.
The precept for presentation's slides is:"Less is more. The less, the better." Because the slide show supports the speaker, not replace her/him, and the audience neither want's to read a book, nor watch a video, but listen to what the speaker has to say.
Enjoy Don McMillan to learn about how to not make PP presentations.
I thought so.
Dimensions and format: 90 cm × 134 cm, landscape orientation. Include a 3 mm bleed (so the document size becomes 90.6 × 134.6 cm). Mark a 4 cm safe area (background graphics should cover the entire canvas, while text, charts, and other elements must not extend beyond the safe area).I thought so.
And despite what I said in my post, I guess the original pictures you got are very much better quality, high resolution actually.
So, as long as you don't have to change them or add anything to them, making posters from them is only a question of resizing those pictures to fit the format.
But to get good results this depends on the target format, and that's what seems to not quite clear by now, at least not to me. If 'posters' means slides for a ("PP") presentation, the resizing job is quite trivial, while, as I said, those pictures are not really recommendable to be a presentation's slide each.
Or shall those actually be printed out on large format paper to be hanged somewhere, like an exhibition or class room?
Then the resizing ain't not trivial, but it's no rocket science neither.
You need to have four things for that:
- high resolution pictures, so upscaling does not produce too much quality loss
- knowing the size of the format the pictures shall be printed on ([mm] x [mm], or "DIN A1", or what format standard you use in your country)
- a software that resizes pictures to the asked size exactly reliably; which is no problem, since on OpenSource there is lots of high quality software to pick from that can do it.
- access to a printer or plotter providing that format; if your U/department does not, there are lots of local "copy/printing" shops offering their machines and services for such jobs. They will tell you, if they prefer the files as Postscript, PDF, PCL, or else, and I bet you a bottle of german beer, there is some opensource software that turns your graphics format into the wanted printing format.
Hence, a real printed poster, no image to be shown with a beamer or slide to be shown with a reflector.
