In my typo3 7.6.19 Website I want to user the flexslider plugin. That works fine, my problem is that the image is a cropped one and not the original file I uploaded.
How can I change it to use the original picture?
Thanks in advance
The plugin sets up a TypoScript constant
plugin.tx_wsflexslider.maxwidth=800px
You can modify this value in your TypoScript template (Module Template > Constant Editor > select "PLUGIN.TX_WSFLEXSLIDER"
About your other problem that is artifacts in the reduced image, I think that when resizing an image from 2550px to 800px, it is probable that the quality will be reduced :) You could check those settings in Install Tool >All Configuration > Image Processing [GFX] and see if you can improve them.
A last word: I would not use images of 2550px, it seems that they will be very heavy! I would try to set a compromise (e.g. plugin.tx_wsflexslider.maxwidth=1200px).
You could also evalutate the extension EXT:image_autoresize https://extensions.typo3.org/extension/image_autoresize/ to automatically resize the images when uploading them and limit the weight or dimensions of the images that your editor will upload.
From this answer typo3 uses crop images how can I avoid this I see that (of course) you can also modify the partial that renders the image and avoid using the TypoScript constants at all, but for the reasons I mentioned above, I would not recommend it.