Curmudgeon

Pretty vague, as there could be many reasons why this would happen, but my guess (since it's probably the most likely) is that you have an active selection and are trying to draw a line outside that selection. Hitting the escape key, or pressing Ctrl+D would cancel the selection. You could then draw lines at will. If this isn't the problem, please report back. And for basic information about the program, pressing the F1 key while running Paint.NET brings up the Paint.NET Documentation, which has explanations of all the inherent tools/effects included with Paint.NET.

another possibility is the Tile Image plugin, with the "Join Edges" box checked

Once you make the selection with anything you do will affect only the selected pixels. So your inability to fill the void area is because it's outside the current selection. Just click Edit> Deselect (or press Ctrl+D) and then you can fill in the void area. However, you're missing out on not trying layers...that's the #1 most important difference over MS Paint. By pressing :AddNewLayer: you can type your text on a new layer and then move the layer around to wherever you want it, and then merge down the layers with :MergeLayerDown: Pressing "F1" while in Paint.NET brings up the help file. From there you can read up on move tools

Nearly identical to one I showed a year ago: Pretty simple to make: Create a new square image Add noise, full intensity and coverage, and no color saturation Motion blur at 90°, centered, and distance of 40~60 (to your own taste) Duplicate this layer...on top layer, rotate the layer 90° and set blending mode to Overlay Merge down, and voilà You can color it the way you're accustomed to It yields this:

easiest way to clear out the treelines is to open the mansion image by itself, and add a new layer under it and bucket fill it with black (or some other contrasting color) so you can see what needs to be erased...then simply use the eraser tool. you can delete the black (or whatever color you chose) layer and resave the image

The most common mistake is when saving, a file type which doesn't preserve transparency is chosen. For example, .jpg and .bmp do not preserve transparency. However, .png, .gif, .tga and .tif all preserve transparency, so select one of them when doing your "save as". If this isn't the problem, let us know

You could do something like this with the Polar Transformation plugin set to "Transform rectangular to polar"

This is already possible if you hold down the shift key which moving the corner handles

First, you should ensure that your paving texture is tileable...you can make it seamless by using "seamless texture generator", "tile image", or "mirror" plugins. Then make a selection you want filled with your paving texture by using or Then, by using either "photo flood fill" or "tile fill addin" plugin, you can seamlessly repeat the paving texture across your selection. All the plugins within quotes can be found using search.

by default .gif images can only contain a maximum of 256 colors, so they are a poor choice if you want to maintain a crisp, detailed image...already mentioned is saving as .png type which is a lossless image type which preserves transparency as well, and is a much better option.

you control where you want the sparkle by using a white dot on a separate layer before running the sparkles plugin I just put a white dot in the area I wanted the sparkle on a new layer above the background...then run the sparkles plugin and configure it the way I want it and voilà. After the sparkle is there you can make it shine using other techniques like glow or blend modes

just use and then image > crop to selection jpg would be the worst choice for quality...png would be much better option

Here's a tutorial link for a similar effect for the Vista aurora look: Click here

Here's a sample tutorial from nearly 3 years ago showing how to recolor things in Paint.NET It was one of the first ways I learned to do it, and I still use this method from time to time, so it may help you. video tutorial on coloring

If the white is only in the background, you could also use alpha mask plugin with "invert mask" checked