You will need to inject IMediaTypeService and IMediaService

Then the following code should give you what you want, I can't say it is the correct or best way, but should work ok :)

    @{
    var folderType = mtype.Get("folder");

    var folders = mediaService.GetPagedOfType(folderType.Id, 0, 20, out var total).Where(m => m.Name == NAMEOFYOURFOLDER);

    var enumerableFolders = folders as IMedia[] ?? folders.ToArray();
    if (enumerableFolders.Any())
    {
        @foreach (var folder in enumerableFolders)
        {
            var imagesInFolder = mediaService.GetPagedChildren(folder.Id, 0, 50, out var totalimages);

            <ul class="list-unstyled">
                @foreach (var image in imagesInFolder)
                {
                    dynamic umbracoFile = JsonConvert.DeserializeObject(image.GetValue<string>(Constants.Conventions.Media.File));

                <li>@umbracoFile.src</li>
                }
            </ul>
        }
    }
}