UI遮挡

[SJLNNU]

感谢开源，这是一款很好的标注工具。在使用过程中发现以下问题：1）功能UI出现了一定程度的遮挡，使得部分图像结果无法编辑，例如无法选中、无法删除。2）图像传入以后出现了大小失真的情况，相比于原图缩小。3）导出图片的名称，能否考虑导出的图片名称和原图的名称一样。

[lujiazho]

This simple demo is more like a toy instead of promoting production and I tried to make it visually pleasing, which may make it not complete convenient to use. 1) But I will try to come up with a way to solve the overlap problem without satisfying aesthetics. If you have better idea please let me know. 2) The downloaded picture is in the same size of the original uploaded one I suppose. 3) I will fix this later.