/* 5.7.3 - Filemanager Image Grid View */
.FileManagerImgGridView {
    display: flex;
    justify-content: start;
    align-items: center;
    gap: 10px;
    cursor: zoom-in;
}
/* 5.7.4 - Filemanager Image List View */
.FileManagerImgListView {
    cursor: zoom-in;
    max-width: 115px;
    box-shadow: 0 0 10px rgba(0,0,0,0.4);
    transition-duration: .5s;
}

    .FileManagerImgListView:hover {
        transition-duration: .5s;
        transform: translateY(5px) scale(1.75);
        border-radius: 3px;
        z-index: 100;
    }

/* 5.7.5 - Filemanager Image Detail */
.FileManagerImgDetail {
    max-height: 280px;
    max-width: 280px;
    border-radius: 5px;
    box-shadow: 0 0 20px rgba(0,0,0,0.4);
    cursor: pointer;
    transition-duration: .5s;
}

    .FileManagerImgDetail:hover {
        transition-duration: .5s;
        transform: scale(1.2);
        max-width: 80%;
        border-radius: 50%;
        box-shadow: 0 0 20px rgba(0,0,0,0.4);
    }

.FileManagerImgDownloadLink {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-left: 10px;
    padding: 5px 10px;
    border-radius: 10px;
    color: var(--bs-primary-inverted);
    background-color: var(--bs-primary);
    box-shadow: 0 0 10px rgba(0 0 0 /.7);
    gap: 5px;
}

    .FileManagerImgDownloadLink a {
        text-decoration: none;
        color: var(--bs-primary-inverted);
    }

using SixLabors.ImageSharp;
using SixLabors.ImageSharp.Processing;

public virtual IActionResult Thumbnail(string path)
    {
        var virtualPath = Path.Combine(_thumbnailFolderRoot);
        var physicalPath = Path.Combine(ConstantVar.webEnv.WebRootPath, virtualPath.Replace('/', '\\'));
        path = Path.Combine(physicalPath, path);
        FileInfo imageInfo = new FileInfo(path);

        int width = 75;
        int height = 75;
        bool KeepRatio = true;

        using (Image image = Image.Load(imageInfo.FullName))
        {

            // Figure out the ratio
            double ratioX = (double)width / (double)image.Width;
            double ratioY = (double)height / (double)image.Height;
            // use whichever multiplier is smaller
            double ratio = ratioX < ratioY ? ratioX : ratioY;

            int newHeight = height;
            int newWidth = width;

            if (KeepRatio)
            {
                // now we can get the new height and width
                newHeight = Convert.ToInt32(image.Height * ratio);
                newWidth = Convert.ToInt32(image.Width * ratio);
            }

            image.Mutate(s => s.Resize(width: newWidth, height: newHeight));
            using (var ms = new MemoryStream())
            {
                image.SaveAsJpeg(ms);
                return File(ms.ToArray(), "image/jpg");
            }
        }
    }