Had the same problem. My image is smaller in width than the post itself and is stretched. This is actually a CSS configuration problem.
If you are using version 0.92 and WordPress 2.5 do as follows:
Go the “Gallery” admin panel then the “Style” sub panel.
Check which style you are currently using (I will take the “Black Minimalism Theme” as an example) and locate the line beginning with
.ngg-imagebrowser img
locate the line
width: 100%;
and comment it or remove it altogether. Replace it with
margin-left: auto !important;
margin-right: auto !important;
You should end up with something like
.ngg-imagebrowser img {
some settings...
/* width: 100%; */
some other settings
margin-left: auto !important;
margin-right: auto !important;
}
Click the “update file” button below and refresh your page. You may need to empty your browser cache for it to work.
If you cannot edit the stylesheet from within WordPress your will need to upload a modified version of the stylesheet via ftp to the proper folder, for instance here : your url/wp-content/nextgen-gallery/css/Black_Minimalism.css
I hope that helps.